Nearly all traction mats are made of a polymer, which is a plastic. Heat is the enemy of plastic, friction causes heat. If you follow the instructions, you’ll know to first clear as much debris as you can from your tires.
Most of these mats can double as a sort of shovel to move crud out of the way. After you’ve cleared everything you can, THEN stick the pair of whichever you buy as far under the tire as you can. Solidly, make sure it’s in there.
After those steps are complete, give your vehicle a little gas and see if it catches the mat. If it doesn’t, immediately stop your vehicle and your tires spinning. Reset the mats by digging, and try again.
A trick is to pull forward slightly and then backwards to give your vehicle some momentum if the mats are placed on your rear tires. Or, the opposite setup if they’re placed on the front.
You may have to do this a few times, but just be patient and remember that heat will melt them. If you follow those steps, you’ll be great!