Remove the existing carpeting and pad and tack strips. Cut into smaller pieces with a carpet knife for easier handling during removal.
Use needle nose pliers to remove all the staples or nails used to secure the old padding to the sub-floor.
Sweep and vacuum the sub-floor thoroughly.
Nail new tack strips around the perimeter of the room, leaving a 3/8-inch gully between the tack strip and the wall.
Lay down carpet pad adhesive around the perimeter of the room. Add carpet pad adhesive at the location of any seams, meaning where two sections of padding have to be butted up against each other to fully cover the floor.
Roll out the carpet pad and press it firmly into the adhesive. Trim away any excess carpet pad.
Bring in the carpet and position it in the room. Leave several inches of excess on three walls and butt one end of the carpet up against the fourth wall. Slice the carpet at the corners so it doesn't bunch up in the corner but lays flat to the wall and the excess rides up each wall.
Use a knee kicker to secure the carpet to the tack strips along the first wall. Set the knee kicker slightly before the tack strip and push down. Hold the knee kicker with one hand and knee the knee kicker forcefully to push the carpet over and onto the tack strip.
Move to the opposite wall and stretch the carpet with a stretcher or by knee kicking the carpet and attach it to the carpet strip.
Knee kick the carpet and attach it to the tack strip on the third wall. Use a stretcher or knee kick the carpet on the last wall to stretch the carpet and attach it to the tack strip.
Slide the double sided wall trimmer between the carpet and the wall so the guard rides along the wall. Push the double sided wall trimmer along the floor to cut the excess carpet.
Push the carpet edge into the gully between the tack strip and the wall with the stair chisel all around the perimeter of the room.
Check both sections of carpet so the pile goes in the same direction. Make sure both pieces of carpet have clean and straight edges. Trim the pieces to achieve clean edges with a row finder tool or a cushion back cutter.
Apply seam sealer and allow it to dry according to the manufacturer's instructions.
Lay seam tape under the carpet so each section of carpet covers half of the seam tape.
Slide the seam iron under the carpet pieces. Push the seam iron up the length of the tape very slowly, so it has time to thoroughly heat the seam tape. Push the seam iron up a few inches and tug the carpet section behind the iron together to help them adhere to one another. Push the iron up a few more inches and repeat this process. Continue until the entire seam is complete.
Roll firmly over the seamed section to push the carpet pieces together and into the heated seam tape.