If you are replacing a metal cutting edge, use that as a guide or template. Center it on the polyurethane blade and mark the holes with a permanent marker. Then use a drill with a spade bit of the proper diameter for your mounting hardware, and plunge the bit at medium speed to cut the holes.
Some customers like to install the old metal blade over the top of the polyurethane blade. You will likely need longer bolts if you choose to install in this manner.
The polyurethane cutting edge should not have a significant amount of down pressure against the ground when it is in use. It should “ride” along the surface, clearing the snow and ice.
Don’t forget that you can flip the poly blade over once it’s worn, to double the life.