Clean the floor thoroughly where you're going to lay the rug. Make sure the floor is dry. Put the rug in place.
Fold back one side of the rug by about 6 inches, so the underside is facing up. Peel off a section of tape big enough to span the side, minus about 6 inches on each end. Press the sticky side of the tape to the back of the rug, about 1 inch inside the edge.
Peel off the waxy paper from the top of the tape, exposing the sticky surface under it. Immediately fold the edge of the rug back down and press it into place on the floor.
Move to each side of the rug and repeat the process. When you fold back the edge of the rug, take care not to pull up the tape you've already laid. Tape each side of the rug.