The easiest way to remove/install the belly pan is to first back off the two bolts that hold the the rear mount (tongue) about 1/2" or just before they fall out.

Without doing that, you're having to align three solidly mounted things (the top of the pan above the grill, the lower rubber mounts, and the rear tongue mount) which almost always ends up with the top of the pan hitting the radiator cover before the lower mounts can engage.

With the rear mount loose, you can engage the rear and have much more flexibility to lower the rear to get the top in place while engageing the lower mounts. No more having to force anything or hold your tongue just right. Easy Peasy.