Used Powerbook g4 and need lots of help!!

I was given an old Powerbook g4 from my church. The power supply was toast so i fixed it. Now I have a working computer but know nothing about it. I was not given any disks or any thing. I would like to try and clean it up (back to factory) and let my children use it. I don't know where to even begin. I have never owned an apple anything. Heck the last time i touched any thing apple it was still called a "Macintosh". Is there anything I can do with out boot disks? Please remember I'm a PC guy so I know NOTHING about apples OS or even how to tell what OS it has. Thanks