Free will is the idea that there is a "you" and you are the author of your actions, or at least you can significantly influence your actions.
Of course, your actions are authored by the neurons in your brain but most people speak as if there is more to it than that. As if there is a "you" that exists outside the brain.
One of the debates around free will centers on an idea that free will means actions must be physically random. So, I think people understand that probability and randomness are really important pieces to understanding free will.
The missing link is understanding that probability is a state of mind. It doesn't matter that the physics is deterministic. (Deterministic physics is indeed also responsible for my current unique perception of my consciousness, so deterministic physics can do a whole heckuva lot.)
So, yes, my moment-by-moment decisions in the sea of the universe's physics and other conscious agents are determined by physics, but to all possible computational agents my moment-by-moment decisions and their affect on reality are weighted random.
That’s why it’s called free “will”. Will is an internal concept, it’s your desire determination, etc for something to happen.
Randomness is not really central to this discussion. What matters is the source, not whether the source is random or deterministic.