ADMINISTRATE
Users, User Accounts, Usernames, Home, Root, SuperUserDO (sudo)
+ Add User
Manage Users & Groups graphically by installing and using GNOME System Tools
+ Backup
Removable Media, Smartphones, Saving, Settings and Backup Applications
+ Delete Files
Command-Line, GUI, Trash (or Wastebasket) and Secure Deletion
+ Packages
APT, Deb, dpkg, Flatpak, GNOME Software, Snap and Synaptic
+ Password
Password vs Passphrase, Changing Passwords, and Resetting Passwords
+ Update
Update Settings, Software & Updates, Command-Line, Synaptic, SWORD Project modules
DISPLAY
Arrange Display(s) / Screen(s), Primary, Profiles, Resolution, Refresh rate, Rotation, Reflection
+ Backdrops
Desktop Backgrounds / Wallpaper, Aspect Ratios, Resolution, Dimentions, Color, Style, Changes
+ Locking
Screen Locking / Blanking, Keyboard Shortcut, Screensavers, Power Manager
FONT
Size, Style, Family, Format, Font Manager, Font Viewer, Legalities
+ Fonts Folders
Command Line, GUI, Local Fonts, System-Wide Fonts, Google font(s), Examples
+ Other Fonts
Available Fonts through Synaptic Package Manager, APT, and Microsoft
LAUNCHERS
Also known as shortcuts, Launcher Anatomy, Examples, Editing
+ Create
Launch from Desktop, Launcher from Menu, Examples
+ More
Folders, Java Apps, Shell Scripts, Webpages, Streaming, Symbolic Links, Hard Links
+ Menus
MenuLibre Menu Editor, Examples
PRINT
Printers, Properties, PDFs
+ Share
Linux (or Unix, or Mac OS X) and Windows (Samba)
+ Network
Using CUPS to Install Maintain and Administrate Printers
VIDEO
Ubuntu Restricted Extras, Movies on DVD, DRM-protected HTML5
+ Flash
ActionScript, Animation, Vector Graphics, Ruffle
+ Subscriptions
Streaming Video Services from Australia, Canada, New Zealand, United Kingdom, United States