How do you potty train a 2 year old boy?

He goes potty when I take him to sit on the toilet, thats not a prob. Io say you gotta pee pee or poo poo n pat the front of me or the back, he'll pat too (either one) and I'll take him, he'll go. The problem is that he's taking his diaper off once he poops n hides it n when he pees a lil in the diaper instead of sayin the word or patting himself to let me know.