[Alan Anderson]

Read the Attack 3 joystick's throttle button as "axis 3 (throttle)". It'll give a value between +1 (full back/down) and -1 (full forward/up).

If you want to turn that into a value between 0 and 1, just subtract one and divide by negative two.

Is that enough information? I'm not sure if you're asking how to read the throttle control, or how to set the speed of a motor, or something else.