To do basic dynamic simulation you need to acquire the following concepts:
1. Basic Synchronous Machine Theory
2. PSS/E Dynamic Simulation Process, activities, commands, etc.
3. Planning/Operation Criteria of the power system
4. Interpretation of contingencies (based on the criteria) in PSS/E.
To achieve the knowledge in (1) you may refer to the programs manual/application guide. For (2), and (3) Kundur has an excellent discussion of sample criteria in his book. Hope this helps.
Advanced knowledge of dynamic simulation process includes: Understanding the dynamics and operation of controls such as governors, exciters, power system stabilizers, etc.
When doing transient stability simulations, obtaining the skill does not necessarily relies on software alone. It involves the power system dynamics and stability knowledge and a critical thinking attitude to solve any problems.