From the pics, I don't believe there is much that is similar with your vents as would be on my 300E.
Pity, because I had to reconstruct the ENTIRE vent assembly just to change a light bulb, because I had to remove the vent bezel in order to get the whole unit out. By the time I got the assembly out, I had 20 pieces of vent louvers scattered on the floor of the car!
If they are similar, there should be two or four spring-loaded metal clips that hold it in place. Each is at the 12 o'clock and 6 o'clock position behind the left and right vents. Position a flat screwdriver upwards for the top clips and downward for the bottom ones to push and release, and gently pull the vents out towards you.
The center knob on mine has an eccentric lever system attached with a small screw. Loosen the screw to take the whole vent assembly out. There should be enough room to get your hand inside and work the lever to make sure there isn't any binding. Then check the knob also.
I don't remember much else as I sat down on the kitchen table with a 6-pack of beer to keep me company as I reassembled the unit together...
2009 ML350 (84K) - Family vehicle
2001 CLK430 Cabriolet (71K) - Wife's car
2005 BMW 645CI (124K) - My daily driver
2012 Mustang V6 (60K) - Daughter's car