How do you beat chernabog in Kingdom Hearts 1

you attack his head remember the order of his attacks the only way you can beat him is find the a key blade that is in hollow bastion the only way to get the blade is to beat hollow bastion go to the place where the keyhole was turn right youl see some stairs go up them youl find some chest go to the middle one open it then ahtach it then go back to the end of the world then select the place where you go to the place where you face him then you will go down face those heartless [ warning there tough] then go thrue the door then youl see en illusion of destiny islands then be prepared youl face ansem then you will see a barriar then you will go thrue while donld and goofy tri but falled the you will face a dark side then without you will face ansem then go back where treverse town was youl go see moogles youl see a key blade [it is the ultimite key blade] find the ingreidiots to sythzize it then you beat the GAME.