a bit more info ...
Aftrer removing the cover place it face down on a soft cloth to avoid damaging the chrome finished detail

, seperate the upper and lower halves by unscrewing 8 bolts on the underside.
You can then remove and replace the air filter.
NOTE : VW advise caution when replacing the bolts that secure the two halves of the cover together, which are "self tapping" - It is easy to over tighten them and strip the thread, especially if using a cordless screwdriver
They should be tightened to a maximum of 3Nm !
Refit the cover in the opposite direction to removal, being careful not to press down on anything other than directly over the four mounting points - rear ones first, then front.