This single exercise contains lots of brainstorming. From the scratch, we did requirement gathering. We got just 2 lines of problem statement but we made SRS of 20 pages. Bravo!!
After that, to ensure that we only got that many classes that we actually want in our system we did noun analysis. This is very efficient way to extract names of classes from SRS and our problem statement.
And finally after all these, there are lots of diagrams one by one in sequence.
That’s all. (But it is not that easy.)