The next button is in the bottom right. It appears when your mouse pointer is near it. Hover your mouse over the black bar on the left to get an info message about the shown character.
To show that I'm not done with PaP, here's some designs for the TamaTerrorz and PALPercy. FYI: I'm working on fixing the opening cutscene, since it has some problem where it crashes the tab when it tries to load, so i'm completely reworking that.
