Here's a basic crash course, written so that you can follow along, step-by-step.
Installation on OS X
brew install tmux
tmux new-session -s foo
Creates a session named foo.
Congrats! You are now attached to a session and you should see one tmux window.
A bit of terminology: you create a session which can have one or more windows, which we'll see below. Within a window, you can split it into panes.
(I'll use ^ to indicate "Ctrl", so ^b means Ctrl+b)
will create a new window. You should see a status bar at the bottom of your terminal listing out the current windows. Do it again to create another.
Now you have multiple ways to switch between windows:
|switches to window 1|
|switches to window 2|
|choose window from a list|
|(lower case "L") go to last selected window|
Next, you probably want to split your current window into panes.
To switch panes:
|Go to the "next" pane|
|Go to the pane above. Try left, right, and down as well.|
Here's a cool feature of tmux that you might be familiar with if you've ever used screen. You can detach from a session and reattach at a later time, with all of your windows and panes intact!
|Detach from current session|
Finally, to reattach to a session
|Reattach to a session named foo|
Hope you found this to be useful. Please let me know if you have any questions. Thanks!