Measure the wall length. Cut the tack strip with a saw in between a few tacks to the desired length.
Lay the tack strip in place. Hammer one of the nails in the tack strip into the subfloor with a quick strike.
Place a level on the floor against the tack strip. Make sure the strip is straight and hammer a second nail into the floor.
Hammer all nails into the subfloor to attach the tack strip to the subfloor. Continue this process all around the room to complete the tack strip installation.