For installing PoodLL plugins in general, check this page
http://poodll.com/documentation/1.0/2/installing-poodll/
This page contains instructions for how to do a manual install of the PoodLL repository, as well as a setup guide for the repository instances
http://poodll.com/documentation/1.0/27/poodll-repository/
The two screenshots I posted show how to get to the defined roles page for students, and then what the capabilities *should* look like. (NB The language strings are messed up so the titles look funny. My bad). If it already looks like this, then you have a different problem. If it doesn't look like this, clicking the "edit" button at the top of the page will allow you add capabilities.
If you have a different problem check that you have followed the steps in this doc:
http://poodll.com/documentation/1.0/23/poodll-anywhere-for-atto/
