I recently installed Ubuntu 20.04 LTS (Focal Fossa) (dated 23 April 2020), with the intention of creating a VM using VirtualBox 6.0.22 (released 15 May 2020). I had issues with VirtualBox guest additions, and this is how I solved it.
If you've had fun with Docker containers, I now introduce you to Kubernetes and wish you the best of luck. I'm still learning myself! I decided to install IBM Cloud Private Community Edition following the Installation guide at IBM's Knowledge Center.