Installation

sudo apt-get install tmux

Commands

In tmux, hit the prefix ctrl+b (my modified prefix is ctrl+a) and then: ###Sessions

:new<CR>  new session
s  list sessions
$  name session

###Windows (tabs)

c  create window
w  list windows
n  next window
p  previous window
f  find window
,  name window
&  kill window

Panes (splits)

%  vertical split
"  horizontal split

o  swap panes
q  show pane numbers
x  kill pane
+  break pane into window (e.g. to select text by mouse to copy)
-  restore pane from window
⍽  space - toggle between layouts

Set up scrolling and fix Shift-F5, Shift-Fn in mc

put this command in your ~/.tmux.conf

set -g mouse on    

# Lower escape timing from 500ms to 50ms for quicker response to scroll-buffer access.
set -s escape-time 50

# Fix Shift+{Fn} keys in Midnight commander
setw -g xterm-keys on

For older versions of tmux use

setw -g mode-mouse on

as a first line. Otherwise you get

... .tmux.conf:1: unknown option: mode-mouse ...