Answer:
The brain follows signals through the nervous system. The nervous system sends a signal of what we want to do seconds before it happens, to ensure quick reactions. For instance, when we touch a stove, our nervous system already sent the signal seconds ago in an attempt to prevent your skin cells from being burned off. That is why we immediately pull back from intense heat unless we tell ourselves "wait, no!" before the process is over.
I hope this helps! Have an awesome day.