There is a pot (the knob) on the end. If you turn that it will turn a servo, or the throttle on the esc. It has a (iirc) 6v or 6s lipo input. You may want to make a rubber band/spring mechanism that returns it to neutral after giving it throttle. That's what I plan to do.
But you can only give full throttle or no throttle at all, right?
Still got a few questions, to make it easier, I made something in Paint. Are all these things right that I'm describing in this pic? And what are those things where ??? stands?