To achieve the right grip you need to.
Tack down carpet on stairs.
These will grip the carpet backing and hold it in place.
Measure the width of the stair and length.
Cut your tack strips into lengths which are 4 inches shorter than the width of your carpet runner allocate two strips for each step of your staircase.
If the carpet padding is tacked on simply pull it up and dispose.
Prepare your stairs for carpet installation by installing tack strips thin pieces of wood resembling yardsticks with tacks pointing upward.
Working from top to bottom apply removable carpet glue with a glue gun and adhere the piece to the stair.
Pull the carpet tight and run a row of staples along the top of the riser where it meets the tread of the stair.
Cut the carpet to fit the bottom of each stair the area where the foot will fall.
Use the knee kicker to pull the carpet tight as you place another row of staples in the corner between the riser and the tread.