How in-depth should the essays be?
Your essay is short (you have only 45 minutes), so you won't be able to cover every possible argument, rebuttal and example. When you start the test set aside a few minutes to set up the points and examples. You do not have to cover every idea/concept. Most essay students do not have time to cover everything they would like to cover. Choose the most persuasive relevant points and examples to use. The essay graders do not expect you to go in-depth on every topic.
The most important concern here is that you do not go off of the main subject. Stay focused on the topic. Do not either go off on tangential arguments or excessively focus on one example.
Where should I get examples?
The instructions (with only a few exceptions) allow you to draw upon your personal experiences in developing your answer to each essay question. This practice is acceptable, but don't overdo it. You should generally rely more on academic knowledge than personal experiences.