This page is a brief description of how to use the PyMOL visualization program. It is not currently organized in any real, cohesive way, since I am just learning this program myself.
I will focus primarily on the Python- and command- interfaces, since you can poke around with the point-and-click buttons.
To get help, type
This will provide an overview of allowable commands if <topic> is omitted, or a detailed description of <topic> if you provide it (and, of course, if that topic exists in PyMOL).
You can load structures in several ways. A very common way is to use the load command. Use it as follows:
load <filename>, [<label>]
where <filename> is the name of the file you want to load and <label> is the name you want it to appear under on the right-hand side of the PyMOL window.