Install PostgreSQL
If you created a VM, make sure you are running these steps as the normal user in that VM; not on the host system.
These instructions are for Pop!_OS, they should be similar for Ubuntu.
Install
Follow the instructions on Digital Ocean's Website.
One thing I did notice during the install:
Data page checksums are disabled.
I remember something about "the checksums require more processing power but insure data integrity" or something like that.
Since this is a dev/test system, I'm not going to worry too much about that.
Creating a New Role
Follow the Digital Ocean instruction BUT use the "normal" userid you created when you created the VM (or system) and say "y" to make it a "superuser".