Is this a newly built home or just new to you?

The reason I ask is that if the house is older and just new to you, it would be worthwhile to call a certified chimney sweep. They would inpect/clean your chimney as well as answer all of your questions on the operation of your fireplace.

Fireplaces are very dangerous so be careful.

Best to you.

From what you describe, the flue is obviously to open the chimney. The switch for the motor sounds like a fan to circulate air that's warmed by the fireplace and push it back into the room. The Open / Close lever sounds like a draft control so that you don't get a wind tunnel effect through the doors. On mine, this lever allows fresh air from outside to come in under the fire, thus preventing the fire from pulling all of its air from inside the house. This prevents your house from getting chilled, causing the thermostat to compensate for all the warm air lost up the chimney.