Can we start with a definition of 'free will' first please? Can someone who believes in it, define it, and can someone who also believes, second the definition? Can you also point out an example of where free will can be clearly distinguished from a complex reaction to stimuli? Can you suggest how 'free will' is free from external influence?
I would say that 'free will' does not exist, because people have bad moods. If the will was 'free' people would never choose to be angry. Anger is a reaction, not a chosen frame of mind.
I would also say 'free will' does not exist because while being a complex machine, we still are a machine, with inputs, and outputs, and the output (our speech, manner, and personality) depends a lot on our inputs (envirnonment and experiences).
So, please, that definition. Please back up any claim that 'choice' expresses free will, or I might ask you if a die 'chooses' which face to land on, ....