When in dragon mode:
Press number 1 (the one close to QWE) to change attack mode to Flames
Press number 2 to change attack mode to Fireball
Press number 3 to change attack mode to Wing slash
Left mouse button - Attack
E - Grab peds/vehicles (vehicles only with big dragon)
R - Eat/bite peds
When in normal ped mode:
Hold R when aiming to a Ally big dragon to start the Ride feature (message must appear in right bottom corner)
Hold Space while riding a dragon to jump out
Flight controls:
W, A, S and D - Control movement
Mouse - Control camera and dragon direction
You can change some hotkeys in the self-generated .ini file