I'm a mac newbie. please help.

[maug58@dial.pipex.com (xix)]

I just got my first Mac. A second hand Performa 5200. There is no
manual  that came with it.  Upon installing it, I found that my there
is only one port that support either the keyboard or the mouse.  I
find it very confusing as the computer need both to run, but there is
only one that it supports.  The other ports are not compatible with
the mouse or keyboard's connector.    Please help, I dont know where
else to turn to. 

A mac newbie in need....