Hi @guava01,
Those steps you linked include setting up Docker which is used in our development environment to run the database, and also some other useful systems required for a full developer environment. If you followed the steps and everything worked correctly you should be able to run make run, which will start up the required Docker containers, start the server and build the webapp client. When done, run make stop to stop the server.
You can also setup your own Postgres or MySQL database that doesn't use a Docker image and then in config/config.json you can specify the DriverName and the DataSource. Take a look at the production install steps for an idea of how to set up the database.