sql, pseudocode

Oct 2012
I have one task for SQL:

one course has more topics.
There are more lectures to one topic.
There are more students to a lecture.
One student is attending more lectures. (S_L entity!)

Please, if each lecture is paid particulary, how much does each course earn?
How to write pseudocode?

I tried this: main problem- still have no INNER FEELING how sql works.
Seems a little bit tricky, at least for now.

Many thanks if someone would have nerves fora beginner!