Loaded as one of the final steps in the boot process.
Often just called X.
A service called the Display Manager keeps track of the displays being provided and loads the X server (so-called, because it provides graphical services to applications, sometimes called X clients). The display manager also handles graphical logins and starts the appropriate desktop environment after a user logs in.
Old, being replaced by simpler version like Wayland
Desktop Environment
A session manager (starts and maintains the components of the graphical session)
Window manager (controls the placement and movement of windows, window title-bars, and controls).
Set of utilities
GNOME is a popular desktop environment (Alternatives include for example KDE)
GNOME
Desktop Environment (default in Red Hat Enterprise Linux (RHEL), Fedora, CentOS, SUSE Linux Enterprise, Ubuntu and Debian)
The default display manager for GNOME is called gdm
Can be customized using Settings and tools like gnome-tweaks
Nautilus (File Manager)
Is used to navigate the file system
Lets you access different locations on your computer and the network
Can be opened from terminal (nautilus)
When a file is double-clicked is opened with a text editor (The default text editor in GNOME is gedit) (This can be changed in the configuration)
Deleting files sends them to .local/share/Trash/files/
A file can also be permanently deleted (shift + delete) and the trash can be emptied.