You have to have SourceBans installed on the Gmod server and configured to work with your database.
There are various instructions around the net for that.
Then ULib and ULX need to be installed for the Gmod server.
That release adds a ulx command that works with Sourcebans.
Sourcebans does your mysql database addition/monitoring for you, not ULX.
I'm not sure why that isn't clear to you in the release post.