Appearance Add an extra font for all users — Add extra fonts for all users. Add an extra font for individual users — Add extra fonts for individual users. Add extra backgrounds — How do I make extra backgrounds available to my users? Change the lock screen shield — Change the background of the lock screen shield. Lock the screen when the user is idle — Make the screen automatically lock, so the user must enter a password after being idle. Set custom background — Change the default desktop background for all users. Set default favorite applications — Customize the default favorites in the Activities overview. More Information GNOME System Administration Guide — A guide for GNOME 3 system administrators.