Howtoforge published a guide about setting up Ubuntu 20.04 LTS (Focal Fossa) server.
How to Install Ubuntu 20.04 LTS (Focal Fossa) Server
This tutorial shows the installation of an Ubuntu 20.04 base server in detail with many screenshots. This tutorial uses the LTS branch which gets updates for 5 years from Ubuntu and is recommended for use on servers.
How to Install Ubuntu 20.04 LTS (Focal Fossa) Server