normally when fitting a tire, you put the bead on one side in the "gutter" in the center of the rim where the diameter is narrower while you lever on the bead on the second side. leaving the first bead loose and un-seated while you pop on the second bead makes it pretty easy.

rims with thick rim tape designed to seal with tubeless tires have much less gutter, so it's a bit more difficult to squeeze the last bit of the tire onto the rim. they're compatible, just difficult to work with.