2024 LE AWD how to read auxiliary coolant tank?

From the front (eyes low like near radiator...

I see the tank (front view) 3 to 9 is full of fluid, 12 to 3 is full of fluid, 9 to 12 is empty.
So it looks like 9:00, full the long way between hands, empty the short way.
(Gorgeous with HP flashlight!)

How do it work?

Is there a vertical baffle for ?return? that overflows into the main tank?

Is it truly marked Min/Max both or similar? Front/side?

Special fill/refill procedure?

Is that simply a vent to the left (9-ish)?
Need pressure or pressurizing?

THX all!