Install A Desktop (GUI) On An Ubuntu Server

How To Install A Desktop (GUI) On An Ubuntu Server

sudo apt-get update && sudo apt-get upgrade
sudo apt-get install tasksel
sudo apt-get install slim
sudo apt-get install lightdm
tasksel

# A colorful interface will launch. Use the arrow key to scroll down the list and find Ubuntu desktop. Use the Space key to select it, press Tab to select OK at the bottom, then press Enter. The system will install the software and reboot, giving you a graphical login screen generated by your default display manager. In our case, it’s SLiM.
Enter your login credentials. Use F1 to switch between GUIs if you have multiple interfaces installed.

sudo apt-get install kde-plasma-desktop
sudo service display_manager start
sudo tasksel install ubuntu-mate-core
sudo service display_manager start
sudo service display_manager stop
sudo tasksel install lubuntu-core
tasksel

# Use the arrow keys to highlight the Lubuntu GUI you want to use. Press the space bar to select, then Tab to the OK button and press Enter.

Launch the GUI with:

sudo service display_manager start
sudo service display_manager stop

MORE ON: https://phoenixnap.com/kb/how-to-install-a-gui-on-ubuntu