Depending on your SIS you can either sync through API or just use data uploads via SFTP.
Once users have been synced and you have turned on badges for the schools/grades you want, you will set your chromebooks for that building's ou to use Clever SAML SSO. There is a setup wizard that will walk you through the steps, it is very straightforward.
Although you say you do not need any other features, if you are setting up Clever I'd strongly recommend looking into rostering your various other third party apps through it. I cannot stress enough how much of a time saver it is, and how nice it is to have all of our rostering done through a single pane of glass. You pick the app you're using, tell it what grades, buildings, or teachers to share it with, and you're done. All of the school accounts you need for that website are now automatically syncing and updating whenever changes are made from your Clever data uploads/syncs. Even for our students who do not use badge login, we set their homepage to the Clever portal so they get a full menu of our apps when they log in.