Mark the center of each stair. Center a tackless strip on the back of each stair tread and about one inch in from the back vertical of the stair tread. Leave about 3/4 inch on each side of the stair tread without a tackless strip. Repeat this on all the stairs where you are installing the carpet.
Place a second tackless strip on the front of each riser. Again leave about 3/4 inch on each side and about 1 inch up from the horizontal part of the stair tread. Repeat for all of the stair treads.
Cut a piece of carpet pad for each step. It should be long enough to go from the front of the tackless strip on the horizontal part of the step to the top of the tackless strip attached to the vertical wood.
Attach the carpet pads with staples. Each staple should be about six inches apart.
Tack the carpet in place at the back of the first step. Place a carpet tack about every four inches. Make sure the first step is secure when installing your stair carpet for extra safety.
Press the carpet into the tackless strip at the back of the first stair. Bring the carpet forward enough to press it into the tackless strip on the horizontal part of the first step. Don't press the carpet back into the nose of the stair tread.
Continue until the carpet covers all the stairs. Secure the carpet on the riser of the last step with staples placed about four inches apart.