Roll up the removed carpet fasten it with a piece of duct tape to keep it from unrolling and dispose of it in a contractor bag.
Tack down carpet on stairs.
Prepare the stairs using tack strips and thin pieces of wood similar to yardsticks with tacks pointing upwardm to hold your carpet in place.
These will grip the carpet backing and hold it in place.
Working from top to bottom apply removable carpet glue with a glue gun and adhere the piece to the stair.
To achieve the right grip you need to.
Prepare your stairs for carpet installation by installing tack strips thin pieces of wood resembling yardsticks with tacks pointing upward.
Grab a sharp utility knife and a measuring tape and get to work.
If the carpet padding is tacked on simply pull it up and dispose.
Measure the width of the stair and length.
Pull the carpet tight and run a row of staples along the top of the riser where it meets the tread of the stair.