screen command

to switch off the startup message in the screen command,

sudo emacs -nw /etc/screenrc
and uncomment the line,
startup_message off

to enable scroll mode do Ctrl+A and ESC
Press ESC to return to normal mode.

To reattach a screen that is attached else where do:
screen -d

The following commands can be used for navigation purposes. Reference

h -    Move the cursor left by one character
j -    Move the cursor down by one line
k -    Move the cursor up by one line
l -    Move the cursor right by one character
0 -    Move to the beginning of the current line
$ -    Move to the end of the current line.
G -    Moves to the specified line 
       (defaults to the end of the buffer).
C-u -  Scrolls a half page up.
C-b -  Scrolls a full page up.
C-d -  Scrolls a half page down.
C-f -  Scrolls the full page down.

By writing the following line to .screenrc in $HOME you can change number of lines that are stored in the scrolling buffer.

defscrollback 5000