A tutorial on installing the PostGIS Extension for PostgreSQL was published by Unixcop.

How to Install the PostGIS Extension for PostgreSQL

In this post, you will learn how to install PostGIS Extension for PostgreSQL using Ubuntu 22.04, but it is perfectly applicable to other systems. According to the project website PostGIS is a spatial database extender for PostgreSQL object-relational database. It adds support for geographic objects allowing location queries to be run in SQL. 

How to Install the PostGIS Extension for PostgreSQL - Unix / Linux the admins Tutorials