Unable to upload e-books into device

Question

I have a Mambo Mano MP3 player with 2 GHz memory.I have figured out everything EXCEPT the e-book reader! # 1. Does anyone know what type format is required for e-books to work? There are 10 or more e-book formats. Also # 2 I have tried everything I can, trying to understand the **&(%%%$!!& Chinese instruction manual that comes with it. I have found 3 different ones and all are useless!!! I have also been trying to upgrade the firmware! Any help here would be appreciated as well. #3 Is there a way to reformat the player back to the original factory specs? Any help on any item would be wonderful. Thank you, Nightfire