Install a desktop

Optional step
Depending on what you are going to use your Pi for, you may want a desktop environment to run graphical applications. Nevertheless, this step is completely optional.

First you need to ensure your packages are updated to the latest version, run:

sudo apt update
sudo apt upgrade

Then, you can use the apt install command to install a desktop environment.

Here are some popular and lightweight options:

sudo apt install xubuntu-desktop
sudo apt install lubuntu-desktop
sudo apt install kubuntu-desktop

Learn more about Ubuntu flavours.

Once the install finishes, reboot your pi with:

sudo reboot

And your new desktop will come up automatically