i dont think you need to take the pieces off that you circled.
if you look at the second pic it shows it w/o the pieces.
those are just trim pieces and are only there to make it look nice and come in many different finishes. i.e., mine are brushed aluminum.
you should take out the radio. if you have the stock radio you will need radio removal keys. or you can go to a vw dealer and they can do it for you for free.
once the radio is out you can see the space more clearly. most likely the pocket just snaps into place.
now if you wanted to remove the cage completely so you don't have to sit in you car if you need to work on it. you will need to take off the glove box. ( 3 screws on the botom, and 3 just inside above the door there are 3. the two pieces of trim should be removed that cover the ends of the dash closest to the doors should come off. they pop off starting from the edge closest to you if you are sitting in the seat. then there are 3 screws under the dash trim along the bottom edge. this should allow you take take the trim off from under the steering wheel.
with all that off, you need to remove the hvac cover, that pops off, just use a screwdriver carefully. there are 4 screws that hold the hvac to the radio cage. and there are 4 screws that hold the cage to the dash. and there might be two more screws that hold the cage dash and glove box on, and the cage to the center console. just above the ash tray.
you should be able to slide out the radio cage and see what is holding the pocket in. and now you have a radio cage to work with in fabbing your screen into it for however way you choose to do it.
there are alot of steps, but once you do it once its a piece of cake and takes like 10 min, if that.
i think there are pictures of all this on vwvortex.
hope this helps