Measure the length of the seam you are trying to edge, using a tape measure. Measure from wall to wall along the surface of the flooring.
Cut the aluminum bar carpet edging to the length of the distance between the two walls. Use a hacksaw to cut it to length.
Lay the carpet edging over the seam between the two flooring materials. Center the screws in the aluminum bar edging directly over the seam all the way along the seam's length.
Place a screw in the predrilled holes at each end of the edging with your fingers. Drive these screws into the floor with an electric screw gun. Don't over-tighten the screws, or you'll strip the subfloor, and the aluminum edging won't get tight. Once the two end screws have been installed, install screws in all the holes in between them.