Pushing Stage

Hi im a FTM 32+5 with my rainbow boy 💙

I just read an article on pushing and I'm completely lost on it now. I thought you just pushed whenever and the baby comes out. Now im seeing u have to push with contractions? And it takes a long time cuz you have to wait for contractions? Im reading birth stories where almost everyone experiences contractions back to back so how would it take so long for a baby to come out? Im so not getting this at all i need some explanations lol