On another topic on EVI-style fingerings you'll find a link to the exact mappings we use.
Basically, your left hand replaces the things you would have done with a trumpet embouchure, and your right hand controls what would be the valves.
In the base position, you only hold keys 2 and 3, those below your left middle finger and your left ring finger, and this plays a C.
On the left hand, you can go down by 5 half-tones (add the left index finger). Meanwhile, your left thumb selects the current octave (a specific mode with reversed direction will soon be available). In addition, like with the EWI, you can go up by 1 half-tone (remove the left middle or ring finger, or add the left pinky finger) at most.
On the right hand, you can use the index, middle, and ring finger like you would on the valves of a trumpet (to go down 1 tone, 1/2 tone, and 1+1/2 tone, respectively). In addition, putting the right pinky finger adds 2 half-tones (like the 1st trill on the EWI).
To sum it up, from the base position (press only the left middle and ring finger keys), pressing or releasing other keys will add or subtract a certain amount of half-tones from the C pitch:
Left Hand (embouchure)
- Press Key 1 (left index finger): -5
- Release Key 2 (left middle finger) or Key 3 (left ring finger), or Press Key 4 (left pinky): +1 (non-cumulative)
Right Hand (valves)
- Press Key 5 (right index finger): -2 (valve 1)
- Press Key 6 (right middle finger): -1 (valve 2)
- Press Key 7 (right ring finger): -3 (valve 3)
- Press Key 8 (right pinky): +2
We'll try to quickly release some more polished documentation about it.
In the future we'd also like to make a tutorial video on this, but we're not good enough with this fingering to make a convincing demo :).