Wow. Alright, for one, a compound movement is defined as as an exercise that moves the body through more that one joint of movement. Say a squat, which bends you at your ankles knees waist and hips. Now curls on the other hand..not so much. It's been fun teaching you and all, but I think you should look into another strength coach as your current one hasn't even taught you the basics.
To correct you once again a compound lift or exercise is one that hits more than one muscle group at a time, 3 or more preferred. That being said doing a cable curl hits the biceps, forearms, traps, and even the delts some. As you would notice all of which were listed above. But just to make you happy bicep cable curls also makes the wrists move just so you can get multi-joint there.