hawk 70 atv

Hello all, got a problem that I need help with. Took the quad to the place where we purchased the thing from because I couldnt get it to crank & they diagnosed it & found that the rocker arm is broken. They gave me the broken piece, but they said that it basically wasnt worth their time to fix. So I need help on doing this my self. Any help is appreciated. I have not repair manuals or anything so if someone has anything on this or similar to guide me, then please give me a helping hand.
I thank you all as well as my son!!!