Serial search

I reciently accquired an old Blue & White G3 Power Mac. It came without keyboard or mouse so I gambled and purchased one on ebay. Hopefully it will be here anyday. To create a better picture I must say that I haven't a clue what to do with this machine. I know my way around a PC fairly well but this is my first Mac. While waiting for a keyboard I have been trying to find user information about the unit I have. On the back there is a metal plate that gives the Family number as : M5183 and a serial number of : SG9188QIGHZ. My problem is the Family number seems to cover quite a few units and the serial number leads me nowhere. My question, am I looking in the right place for my tower's specs? Hopefully I can find a user's manual on this unit on the internet. At present I don't even know what Operating system is on the tower as the only thing that registers on the monitor is a folder that will not open. I suspect that this is somehow controled by the keyboard. I praying this is the case. Any help would be greatly appreciated. Hummm, I wonder if there is a "Mac for Dummies" book at the local library??