In the PadMu Reader menu when you have a playlist opened, you have the sixth icon from the top that allows you to :

• jump to a piece in the playlist that you want without turning all the pages in each pdf : just click onto the desired piece
• skip a piece previously listed that you don't want to play anymore : just click onto the small "note" icon

Also , it may be useful to have a look at the user manual at the playlist chapter

Thank You