How to tame a dinosaur?

i have this pet dinosaur. his name is rob. i give him cheese everyday. he's really ugly. and he tries to bite my head off. idk why. i tried selling him to the zoo. but they got scared and evacuated the place. its like they've never seen a dinosaur before. anyways. please give me tips on how to train him. it would mean alot. like... my life. thanks.