With the Left Trekker you can "focus" on an enemy (1 enemy)... With the Right Trekker you can Firebreath! With the two levers you can go up and down, forwards/backwards ...
And the A,Y, X and B + D-pad are for 8 hotkeys.
Like in human form: push on one of the 8 hotkeybuttons a little longer (3 sec?) and you can give it a hotkeyfunction (skill, potion, Dragonstone, Crystal Skull or ... so You like it ...
And if this is not clearly, read the Manual
Success!