At the exam a good understanding of the material up to (and including) conjugacy of Cartan subalgebras is expected, meaning that you are able to give definitions, formulate and apply most of the results. A big plus if you also have an idea about the proofs. For the remaining material a basic knowledge suffices, meaning that you are familiar with key concepts and results.?
In the recommended books by Serre and Sepanski the core material roughly corresponds to the following sections:
Serre: 1, 2, 4, 7.1-7.3
Sepanski: 1.1-1.2, 3.1-3.3, 4, 5.1, 6.1-6.2, 7.1