Hi I know you are frustated, but once I tell you how to do it, you will find it real easy. I assume you bought the replacement filter: "Passenger Compartment Pollen Filter", FP-54 (4F1Z-19N619-AA). If you buy it from Ford you will pay alot. I saw it on Ebay for $10:
1. The filter is underneath the windshield and windshield wipers. Under the black airscoop.
2. Leave the hood shut, take a thin blade and pry back the plastic air scoop and the retainers will pup-up. You only have to do this for the half side of the passenger window. Do not go past the center mark towards the driver's side.
3. Open the car hood and you will find three clips holding the upper half and the lower half together. Be careful to hang on to them. You will need them to put them back.
4. There is one(1) screw you will have to remove and again hang on to it.
the screw is at the end of the black platic air scoop behind the McPherson Strut.
5. Lift the two halves of the black airscoop apart and you will the pollen filter staring you in the face. Mine was full of leaves and totally black. It only had 39,000 miles on it. Definitely have it replaced per the recommended interval. Mine was just about totally blocked. I have the 2002 Taurus SW.
I hope this helped. Any questions?