You will also need to download an ISO for a GNU/Linux operating system to be run inside the virtual machine. Lubuntu is often a good choice as being relatively lightweight but with enough out-of-the-box functionality to be used immediately. Lubuntu can be downloaded here.
Double click on the newly created VM; you will be presented with a box to select which operating system to install. Using the folder icon next to the drop-down menu, navigate to and select the ISO you have downloaded.

Select install Lubuntu (or whichever OS you have selected) and follow the instructions. It is safe to “Erase disk and install Lubuntu” as this only happens within the VM, not on your computer.


Remember the username and password you select as we will need these to log in later.
Once the installation has finished and the VM rebooted, we should have a working GNU/Linux system.