How do you give a hand job? SERIOUS QUESTION!?

This is serious. I really like this guy, and he likes me back. He asked me to give him a hand job and idk if i want to but i might because if i were to give one to someone, it would be him. Can somebody PLEASE explain like, what happens? Does a guy like kiss you? Then like pull his pants down or something? And like what do you do exactly during the hand job like how? If he cums do you clean it up after? Do you need lubricant?? Please explain like what happens in detail, and dont say dont do it or anything, i probably wont...i just want to know how just in case! PLEASE HELP!!!!!!!!!!!! thanks