Screen commands

Ctrl-a c	Create new window (shell)
Ctrl-a k	Kill the current window
Ctrl-a w	List all windows (the current window is marked with "*")
Ctrl-a 0-9	Go to a window numbered 0-9
Ctrl-a n	Go to the next window
Ctrl-a Ctrl-a	Toggle between the current and previous window
Ctrl-a [	Start copy mode
Ctrl-a ]	Paste copied text
Ctrl-a ?	Help (display a list of commands)
Ctrl-a Ctrl-	Quit screen
Ctrl-a D	Power detach and logout
Ctrl-a d	Detach but keep shell window open

Use screen -ls to see the available screen sessions.

Use screen -r to reattach to the sessions.
or screen -rd to reattach if the server got confused due to a network outage.
https://unix.stackexchange.com/questions/240444/cant-resume-screen-says-i-am-already-attached