We had the same wonderment until the delivery driver (the dealership provided) did a walk through with me. First he had to stand on the step and push the "on" switch up inside the fan then showed me the control is also on the Heat/AC stat, not sure but we can also reverse the air flow with a dial but again, its up inside the well. Will be separating them out to digital, much easier to monitor for accuracy and use.
I leave the setting at 3 (highest) so I never use that dial.