To install the desktop interface for the Ubuntu server, in the command window, type:
sudo apt install gnome-session
Press
Y to accept the desktop interface settings
To set the default desktop interface, type the command:
sudo update-alternatives --config gdm3.css
Then log out of the currently logged in account with the command:
Logout
After the server restarts, it will go straight to the desktop interface. Now you can click instead of typing commands.
To switch to the command book interface, press the key combination
Ctrl + Alt + F4, return to the desktop interface, press:
Ctrl + Alt + F7