I think that it would help if we rewrote the sentence like this:
"Advise" means to recommend SOMETHING as a course of action.
As you can see, the word "as" introduces the words "a course of action," which refers to "something."
If you are having a problem, you might ask a friend: Could you recommend a course of action for my problem?
Then after your friend gives you his / her advice, you might tell another friend what your first friend suggested and say, "Do you recommend WHAT HE / SHE SUGGESTED as a course of action?"
(As you can see, the function of the word "as" is to introduce "a course of action," and "a course of action" refers to "what he / she suggested.")