If so, you don't have to completely remove the glove box door. When it's ajar, you can bend the sides of the door inward so the knob stoppers pass and the door opens even more giving you access to the cabin filter slot.
If you have to remove it, push the passenger seat all the way back and look under the glove box door with the door closed. There are two plastic pins holding it in. They both pull out inwards. After removing those two pins, the door will just fall out when you open it. If I recall there may be another plastic wire that is attached to it so it won't fall completely on the floor.