How do you Change the Cab Air Filter 2000 Ford F-150?

I have looked underneath and behind the glovebox, I cannot seem to figure out how to open a cab air filter houseing. I don't see how I can get at the cab air filter door, or if there even is access behind the glove box. I feel like it has to be possible, because I change it on my car,

*Problem: I can't seem to find a door or anywhere where you open and replace a cab air filter.

Please help me Ifix community!