All right, the fog is clearing.

I’m glad we can get pushing towards a better understanding.
I’ll try to be brief:
Calvinists believe that God predestines everything that occurs, including the fact that you’re reading this, every thought anyone has ever had, every single particle moving in the universe, etc. All has been decreed by God. (The usual objection at this point is, Then how can we be held responsible if our actions are foreordained? But that is a rabbit trail I would not like to go on at the moment. Suffice it to say for now that Romans 9:19 anticipates the
exact objection.)
Seeing as everything is decreed by God, including all our actions, it follows that we don’t truly have the ability to do other than we actually do,
absolutely speaking. The Calvinist operates with a
compatibilist view of the will, which is defined essentially as
An action is free if and only if the agent performing it acts in accordance with his strongest desires.
Almost all non-Calvinist Christians operate with a
libertarian view of the will, which is defined essentially as
An action is free if and only if the agent performing it could have done otherwise.
So, the difference between the two is that for the libertarian/non-Calvinist, free actions require the absolute ability to do otherwise, whereas for compatibilists/Calvinists, free actions require the
counterfactual ability to do otherwise (e.g. I could have done otherwise if my desires were different). Libertarianism in this respect (i.e. as opposed to political libertarianism) is identical to the notion of free will that the vast majority of people believe.
Alright, when you get the chance, please tell me what I have said, if anything, is unclear.