In a class, you "cover" different topics. That means that the teacher teaches them:
We covered the French Revolution last time.
In a meeting, you "cover" items that need to be discussed:
We have a lot to cover today. Let's get started.
News reporters also "cover" news stories.
Why does the news insist on covering these silly celebrity scandals?
In all of these cases, "covering" something means discussing things that are on a list of things to talk about.