They all build on each other. The first episode (below) was the hardest for me to grasp. I had never heard of Determinism before, and had always assumed we have free will. So if you're new to it, it seems harsh and unnatural. But stick with it. The following 3 episodes clear up a lot of the questions raised in this one. Unfortunately it takes quite some time to type them out so try to be patient with me.
Reasonable Doubts, Episode 29: Free Willy vs The Determinator
Starts at 21:16
Definition of Free Will (24:30): This is the definition that christian apologist and philosopher J.P. Moreland would take: He calls it Libertarian Agency. You are a free agent. Your actions do not have prior causes. You are the unmoved mover if you have free will. You choose to do something. You could have chosen otherwise. Not only can you initiate actions, you can also stop actions, or choose not to act. Basically we're all little gods, in a way.
26:25 Determinism in a nutshell is the opposite of that. There are external and internal forces that influence your behavior. Commonly people think of determinism as you couldn't have done otherwise. You're standing there with the gun pointed at somebody and you're forced to pull the trigger. But really it means simply that there are reasons for your behavior, forces and factors at play, external and internal prior causes. When you are making choices those choices are not uncaused. There is a chain of causes. Your choice is the effect of prior causes.
I’m sure GMN will have a response; but I just feel the desire to chime in.