As @user535733 has mentioned, you've likely not loaded the installation ISO file. Looking at the screenshots, it looks like you may have several issues that will need to be resolved before you can install Ubuntu:
- the system memory is insufficient for Ubuntu Desktop (but okay for Ubuntu Server)
- the video memory is insufficient for Ubuntu Desktop (but okay for Ubuntu Server)
- the storage space (1.49 GB) is insufficient for any modern version of Linux
- the network adapter may be better set as "Bridged"
So, with this in mind, let's go through the process of creating a VirtualBox installation of Ubuntu Server 20.04 from scratch. Many of these steps you've likely already done but, if this is your first Ubuntu VM, it may be good to double-check.
Open VirtualBox (if it's not already open)
Create a new Virtual Machine by pressing "New" (or the equivalent thereof)
Give the VM a descriptive name and ensure it is set to "Linux" and "Ubuntu (64-bit)":
Give the VM at least 2GB of RAM. Ubuntu Server can run with less, but 2GB is a good start:
You can always change this later if needs be.
For the storage, choose "Create a virtual hard disk now" and press "Create":
Choose "VDI (VirtualBox Disk Image)", then "Dynamically Allocated". This will ensure the disk image does not instantly use all the space you will assign.
Set the amount of storage to a number greater than 25GB:
Note: Because the disk image is dynamic, it will not use all this space immediately. It is simply a maximum.
Now the basics are in place for the VM, but you will need to make a couple of changes:
Press the "Settings" icon (with the gear) and choose "System" from the left-side menu. Set the "Processor" to a good number of CPUs, with 2 being good number for a simple VM:
Checking "Enable PAE/NX" may be worthwhile, but not a requirement.
Under Storage, mount the Ubuntu 20.04 ISO that you downloaded to the CD:
You will need to use the
.isofile, not a flash disk with the ISO "burned" to it. If you don't have the ISO, you can download one from Ubuntu.
Ensure "Live CD/DVD" is checked:
For Audio, feel free to disable it if you are running Ubuntu Server
Under Network, select "Bridged Adapter" so that the VM connects to your network. Click "Advanced", then choose "Allow All" under the "Promiscuous Mode" setting. This will make it easier for you to use the VM like a normal server on your network:
Press "OK" to close the settings panel. The other settings can be left as they are for now. You can tweak them later if you wish.
Now that the basic settings are done, you're ready to press "Start" and install Ubuntu Server:
Welcome to Ubuntu Linux 👍🏻