When ratpoison starts you should see an empty X server. To open an x terminal hit C-t c. You can now run shell commands as you would on any terminal. Notice the terminal maximized full screen. C-t ! will run a single shell command and saves you the effort of opening a terminal.
Once you have a couple X programs running, you'll want to navigate between windows. To see what windows are being managed hit C-t w. Each window has a number. You can jump to a window by hitting C-t followed by the window's number. This assumes the window's number is one digit. You can also switch to a window by typing in part of its name. To do this hit C-t '.
ratpoison allows you to cycle through the windows with C-t n and C-t p.
And that concludes a brief introduction on how to use ratpoison. Notice how we didn't have to drag a single window, or click a single maximize button? Beautiful wasn't it? Felt fast? Cool? It's modern computing at its best.