How do you beat the last boss in Resident Evil 5

first you must turn out the light and when he cant find you shoot a rocket at him and when he is holding the missile shoot the missile and then go grab him and hold him wile the other player (or com) stabs him with the needle (may take 2 trys) after you will be in a ship were you will have a button sequence i don't really know the buttons you push there different every time except the last one witch is when sheva is about to fall out of the ship its L and R at the same time. after that you will be in a volcano were he will be infected and you have to run away from him until chris falls down and then sheva has to shoot the guy in the back on his glowing spot (you can do that as chris to but it is hard he it almost always looking at you) after he will jump up by sheva and chris will just have to shoot him to slow him down wile sheva runs she almost falls were the player of sheva must rapidly hit a i think when she is back up chris has to go over to a big boulder and hit some buttons to push it and make a bridge so that sheva can come over to him. after that they both have to shoot the boss until the weekspot shows and then shoot that repeat a few time then you will both get away in a helicopter but its now over you have to hit L and R at the same time when it says to to finish him off with two rockets.