Anyone install LMC rubber floor mats? help please.

[old Chevy guy]

I have a new rubber floor mat for my truck and was trying to put it in today but there seems to be a ton of extra material in the front. seems like it would go all the way up on the firewall even behind all the insulation pads. all that stuff is already in a long time ago and Im not taking it back out. Also if I have to take the tranny out someday Ill have to pull the matt to get the hump out and Im not going to take the whole thing apart under the dash to do that. Just wondering if anybody else has put this in and what you did as far as trimming. Its the mat that goes all the way in under the seats. tried searching the forum but didn't find any info about installing it.