Information on Air Dampers, No heat and upper air vent control rod broken

I picked up a 04 Prius yesterday with this issue.

Before I bought the Prius i noticed the defrost is not working, no air blowing on the front windshield. I looked under the dash and the damper that controls the vent position was still moving based on vent section from the display, but I noticed the physical rod that connects the damper to the piece that spins on the ventilation system was not connected and dangling.

I was trying to manually move the vent selector by hand today,(Just leave it in defrost until fixed) and the selector does not want to move all the way to the defrost setting. It kind of seems like it is jammed,( makes sense as to why the damper rod would come off). How are should the upper vent selector be to spin?

As i am playing with this more, i am noticing that i am having a hard time getting heat to come out of the vents. The lower damper is moving around as selections occur on the display. I am assuming that is working correctly.

My questions are.
Is there a source for diagrams of the ventilation system?

Does the vent control damper have any control over the heat?

What controls that heat in ventilation system?

How are should the upper vent selector be to spin?

Any ideas on what could be causing this?

Thank you!
-Dan