The default prefix is C-b. I'm going to assume that Ctrl-b is your prefix.
Session is a set of windows, plus a notion of which window is current.
Window is a single screen covered with panes. (Once might compare it to a ‘virtual desktop’ or a ‘space’.)
Pane is a rectangular part of a window that runs a specific command, e.g. a shell.
Display a list of keyboard shortcuts:
Ctrl-b ?
Navigate using Vim or Emacs shortcuts, depending on the value of mode-keys. Emacs is the default, and if you want Vim shortcuts for help and copy modes (e.g. j, k, C-u, C-d), add the following line to ~/.tmux.conf:
setw -g mode-keys vi
Any command mentioned in this list can be executed as tmux something or Ctrl-b :something (or added to ~/.tmux.conf).
Creating a session:
tmux new-session -s work
Create a new session that shares all windows with an existing session, but has its own separate notion of which window is current:
tmux new-session -s work2 -t work
Attach to a session:
tmux attach -t work
Detach from a session: Ctrl-b d.
Switch between sessions:
Ctrl-b ( previous session
Ctrl-b ) next session
Ctrl-b L ‘last’ (previously used) session
Ctrl-b s choose a session from a list
Other:
Ctrl-b $ rename the current session
Ctrl-b
Create a window:
Ctrl-b c create a new window
Switch between windows:
Ctrl-b 1 ... switch to window 1, ..., 9, 0
Ctrl-b 9
Ctrl-b 0
Ctrl-b p previous window
Ctrl-b n next window
Ctrl-b l ‘last’ (previously used) window
Ctrl-b w choose window from a list
Switch between windows with a twist:
Ctrl-b Alt-n next window with a bell, activity or
content alert
Ctrl-b Alt-p previous such window
Other:
Ctrl-b , rename the current window
Ctrl-b & kill the current window
Creating a new pane by splitting an existing one:
Ctrl-b " split vertically (top/bottom)
Ctrl-b % split horizontally (left/right)
Switching between panes:
Ctrl-b left go to the next pane on the left
Ctrl-b right (or one of these other directions)
Ctrl-b up
Ctrl-b down
Ctrl-b o go to the next pane (cycle through all of them)
Ctrl-b ; go to the ‘last’ (previously used) pane
Moving panes around:
Ctrl-b { move the current pane to the previous position
Ctrl-b } move the current pane to the next position
Ctrl-b Ctrl-o rotate window ‘up’ (i.e. move all panes)
Ctrl-b Alt-o rotate window ‘down’
Ctrl-b ! move the current pane into a new separate
window (‘break pane’)
Ctrl-b :move-pane -t :3.2
split window 3's pane 2 and move the current pane there
Resizing panes:
Ctrl-b Alt-up, Ctrl-b Alt-down, Ctrl-b Alt-left, Ctrl-b Alt-right
resize by 5 rows/columns
Ctrl-b Ctrl-up, Ctrl-b C-down, Ctrl-b C-left, Ctrl-b Ctrl-right
resize by 1 row/column
Applying predefined layouts:
Ctrl-b Alt-1 switch to even-horizontal layout
Ctrl-b Alt-2 switch to even-vertical layout
Ctrl-b Alt-3 switch to main-horizontal layout
Ctrl-b Alt-4 switch to main-vertical layout
Ctrl-b Alt-5 switch to tiled layout
Ctrl-b space switch to the next layout
Other:
Ctrl-b x kill the current pane
Ctrl-b q display pane numbers for a short while