Hi,
You nailed it. Indeed Playmaker is a great way to create reusable codes.
I think you are underestimating the simplicity of Playmaker
what is it that you want to learn that is not in the video you watched so far?
once you understand what an FSM is, what is an event, what is a transition, and how actions are executed within a state, that's it...any c# skills then comes down to what you can do inside Custom Actions.
To create custom actions, your best starting point is to open the existing actions and study how they are made, the principles are here also very simple.
Let me know what you'd like to understand and I'll try to explain more in details.
Bye,
Jean