How does past present and future work?

I think everything in the past is locked. While the present is free. The future consists only of probabilities. That is how I view fate and I will explain more. 


How can I be sure that the present is free when everything in the past is locked? What happened to cause and effect in a certain order? If we skip the science and use common sense because that is what we base our reality on. Then we know for sure that the past has existed. We know that the future doesn't and is yet to come. But what is the present? A mix of the past and future. It is a mix of existence and nonexistence. I would call the past existence itself. Because it will always be there unchanged and the future is nonexistent. The present is a mix of the two. A state giving allowance for observation &  imagination.​