Can someone explain compatibilism?

I know we have at least one or two philosophers in the house. Would someone be able to explain compatibilism in a way that I can understand?

I’ve read a few things from Dennett and others, and I can’t seem to wrap my head around what they are really saying. It appears that compatibilists are determinists who claim that a type of “free will” exists, but that this type of free will is still illusory and only makes sense in practical terms to address issues related to crime and punishment. I’m just not following.

If anyone has a good grasp of compatibilism and can boil it down to simple terms for simple people like myself, that would be very helpful.