The trim is a push fit. Slender plastic pins in the trim engage with nylon inserts in an underlying plastic support which is in turn screwed to the car. Some care is needed to avoid breaking the pins.
This notch, at the front when fitted, allows insertion of a suitable lever to begin extraction.
This pic shows the trim (inverted) and the black plastic switch panel/trim support which hold its pins.
Finally, these two pics show a pin in close-up. In the second pic, I have extracted one of the nylon "top hats" from the support to illustrate how it all fits together when in place.
