iaroki
Meta key for tmux is Ctl+b!
Panes
To split pane horisontal press Ctrl+b and ".
To split pane vertical press Ctrl+b and %.
Navigate through panes with Ctrl+b and direction; Where direction is one of the arrow keys.
Cycle through the panes with Ctrl+b and o.
Hitting Ctrl+b and q will show you numbered label on top of each pane.
To zoom pane press Ctrl+b and z.
Windows
To create new window press Ctrl+b and c.
To switch between windows press Ctrl+b and #; Where # number of window.
Rename window with Ctrl+b and ,.
Sessions
List available sessions in terminal with tmux ls.
To attach to session write tmux a <session name>.
To detach from running session press Ctrl+b and d.
Rename current session with Ctrl+b and $.
Scrolling buffer
To scroll just hit Ctrl+b and [. Navigate with arrow keys or page keys.
Yet another cool shortcut is Ctrl+b and t which print clock.