Here are unofficial versions of the 2box DrumIt Five and DrumIt Three manuals, adapted for the blind and visually impaired.

DrumIt Five with OS 1.30
DrumIt Five with OS 1.32.4
DrumIt Three with OS 1.32.4

These versions contain a few changes and additions and have been formatted and shortened for better access.
Each setting page is followed by a shortened list of buttons to access it. For example: "press the KIT button then press the DOWN Button 6 times" is referred to as "KIT, DOWN 6"
Each setting title is followed by the corresponding button: B1 to B3 for top buttons, D1 to D3 for dials.

The best way to get an idea of the sounds is to listen to them directly on your computer.
2box offer free .dsnd files on their website here

The DrumIt Five and DrumIt Three can play WAV sounds stored in the .dsnd format, you'll just need to download DrumIt Manager or the 2box DrumIt Editor to preview the sounds. It's possible to open them directly with Audacity or a similar sound editor but the sounds wouldn't be played at the correct pitch.

When DrumIt Manager is installed double click on any .dsnd file to hear a preview. You can also use DKit Manager to listen to .dsnd instruments in more detail. Double click on any dkit file to open it with DKit Manager then click on pad buttons to preview sounds.

You can trigger VST sounds through MIDI or export them as .dsnd files to have them directly on your module. The DrumIt Five and DrumIt Three can do both and each way has its pros and cons.

Best absolute quality: trigger the VST sounds directly in MIDI.
Use: recording tracks for an album. Can edit MIDI notes later and change sounds, risk of crash.

Best ease of use: export the sounds to the module.
Use: for home, rehearsal or playing live. Easy access to sounds from different VSTs without a laptop, no risk of crash.

It will sound great but not 100% identical. The samples will have the same quality as rendered by the VST but they will be played by the module, with slightly different results depending on output (headphones out or direct out for the DrumIt Five) and equipment (headphones impedance). The DrumIt Five and DrumIt Three can play VST quality sounds at 16-bit 44Khz.

Copying new sounds is easy with the 32GB SD card modification, it makes it possible to insert the SD card on your computer and copy files directly.

If you haven't installed the 32GB SD card mod you need to connect the module to a computer with a USB cable. It's the same type of USB cables used for printers:

1. Turn off the module if it's open
2. Connect the USB cable from the module to the computer
3. Press and hold the left button just above the DrumIt Five screen (first of the 3 buttons) then keep pressing and turn on the module, it will start in USB mode.

The module should then appear in the list of external drives on your computer. While it's connected you can copy .dsnd and .dkit files from your computer to the module. When you have finished copying the files, turn off the module and turn it on again the normal way.

You can copy them anywhere, the module will find them.

If you have exported sounds with SDSE you can copy the folders it created that contain the .dsnd files directly to your module to have the sounds already sorted by instrument and sound library. If you have exported at least 3 kit pieces at once SDSE will have created a .dkit file that you can also copy to the module as a starting point for your new kit.

The module has 4GB of memory, which can be expanded to 32GB. It comes with 100 kits and many sound files. Some of the sounds are used for several kits in different ways.

4GB memory: 3.68GB total, 3.52GB used
Cymbals, HiHat: 1.61GB
Kick: 151MB
Loop: 66MB
Perc: 123MB,
Snare: 514MB
Tom: 862MB
WAV songs: 182MB
OS, drumit.dkit (configuration for 100 kits + all unit settings), documentation: 2.75MB

To free some space you can delete sounds, but if you want to delete half of the sounds without leaving any empty pads in kits you would need to remove from kit 7 to 100 as well as all of the sounds that are unique to those kits. It can be done easily with DKit Manager using the Delete tab.

It is an easy modification that you can perform on your DrumIt Five (original) or DrumIt Three module to get an external 32GB SD card reader, similar to the card reader on the DrumIt Five MKII. Once you do it you won't be able to connect the module through USB but you will have an external card reader on the module which is even more convenient and will be able to use several SD cards.

Step by step guide

You can find an excellent step by step guide with pictures on the Unofficial 2Box forum here, and a nice video of the whole process here.

No, only a few cards have been tested to work properly with the module. If you use one of the recommended cards it will work as good (or better) than the original 4GB card you had in your module. Beware of fake/counterfeit cards.
You can find a thread about SD card compatibility on the unofficial 2Box forum

A 32GB card can hold 29.73GB of data. On average a 32GB card can hold about 30 kits from a VST like Superior Drummer 2 and more than 60 kits from EZDrummer or EZX kits in SD2.
By doing the external SD card modification you can have as many 32GB cards as you'd like on the DrumIt Five so you'll only be limited by the amount of kits you can have available at once without switching the card from the external slot.

Averages

kit from a VST with more samples 0.9GB
kit from a VST with more samples, without cymbals and hats 0.4GB
kit from a VST with less samples 0.4GB

You don't need to copy all files from the 4GB card to the new card.

Here's the minimum required on a SD card to be used with the module:

• at least one module firmware file named DrumIt***.bin. The latest version can be found here
• at least one .dkit bank file, usually named DrumIt.dkit. It's used to store module settings and settings for up to 100 kits, you can copy your DrumIt.dkit file from the 4GB card.
• some .dsnd files. They can be placed anywhere on the card but it's recommended to sort them in folders. You can copy the folders created by SDSE directly to the card.

optional:

• individual .dkit files created by SDSE

To assign any sound from another .dsnd to a rim zone:

1. press More + a Tom/Snare button on the module, or More + Trig for the DrumIt Three
2. select a .dsnd that contains the sound you'd like to use
3. press Down to go to ENV then press the button above Sound to select the zone until you hear the sound you'd like to use.

This was a tip from Deacon Daniell on the Unofficial 2Box forum

You can export two versions of the same kick, snare and toms. One without the room/ambiance mics, the other by muting the direct mics and using "AMB" in the SDSE field to append "_AMB" to the ambiance .dsnd.
It can be done on one module using only a single input, by losing the tom rims.
You would need two stereo breakout cables, the same kind used to split tom Inputs on the module to use the tom rims to add more cymbals:

Hosa YPP-117, 1/4 stereo male to separate 1/4 female tip/ring.

and one mono splitter:

Hosa YPP-111, 1/4 stereo male to 2x 1/4 female mono.

To do the room trick with a single tom input, losing the rim:

1. Plug a stereo breakout cable on the Tom input, Hosa YPP-117 or similar.
2. Plug the other stereo breakout cable on the pad, Hosa YPP-117 or similar.
3. Plug the mono splitter in one of the breakout outputs from the pad (red for head), Hosa YPP-111 or similar.
4. Use a mono cable from one of the mono splitter outputs from the pad to the breakout input on the module that will be used for the normal .dsnd without room.
5. Use a mono cable from the other mono splitter output from the pad to the other breakout intput on the module that will be the room .dsnd

For the snare, a slightly different way could be used to be able to keep the snare rim, by using another input on the module.

You would need the same two YPP-117 stereo breakout cables as above, and one stereo splitter:

Hosa YPP-118, 1/4 stereo male to 2x 1/4 stereo female.

To do the room trick for the snare and keep the rim by using another module input for the room:

1. Plug the stereo splitter on the pad, Hosa YPP-118 or similar.
2. Plug a stereo breakout cable on the module input that will be used for the room .dsnd
3. In one of the YPP-118 outputs plug a stereo cable that goes to the Snare Input on the module.
4. In the other YPP-118 output plug a stereo breakout cable, Hosa YPP-117 or similar.
5. Use a mono cable from one of the stereo breakout outputs (red for head) from the pad to the stereo breakout cable plugged in the module input you will use for the room .dsnd

Those are known as o-rings (or toric joints) and can be found online or at your local hardware store. It is possible to find a bag of 50 for less than $3.

The original 2Box o-rings have a 15mm outer diameter, 11mm inner diameter and 2mm thickness. Thinner/smaller ones can also work. Avoid getting them thicker than 2mm because it may not fit.

All the card content is available here

You need to format your SD card using a 32K cluster size. You can use this tool to do it.
http://www.2box-forum.com/index.php?topic=1941.0

If you're familiar with the command line you can also use the following command on Windows:
format E: /FS:FAT32 /A:32K
(replace E: by your SD card reader drive letter)
http://www.2box-forum.com/index.php?topic=755.msg7657#msg7657

The module can work with different types of headphones. Depending on your model of headphones it is perfectly normal to set the volume bewteen 2 and 4 o'clock.

You can visit the official 2Box DrumIt Five FAQ, and the Unofficial 2Box forum