Carpet is commonly made in widths of 12” in Canada. Where necessary different widths can be seamed together with a seaming iron and seam tape (formerly it was sewn together) and it is fixed to a floor over a cushioned undead using nails, tack strips, adhesives, or occasionally decorative metal stair rods, thus distinguishing it from rugs or mats, which are loose-laid floor coverings.
For environmental reasons, the use of wool, natural bindings, natural padding, and formaldehyde-free glues is becoming more common.
Get rid of the old carpet
Start at one end and pull the carpet off the tackles strips and roll it up in sections
Install new tackles strips if it is new construction or you are going over hardwood floor or vinyl around the perimeter of the room, but not in front of doorways.
Put the under pad down in strips that butt up to or reach the tackles strips.
Where the carpet pieces will join, overlap the two pieces, and then using a utility knife or a rented seam cutter, cut through both pieces of carpet, ensuring the edges will match exactly
Use a knee kicker to attach the carpet along one edge
Work the way around the room stretching the carpet over the tackles strips, and trim the carpet near the wall with a utility knife or a wall trimmer.
Using a stair tool, tuck the carpet down into the gap between the tackless strips and the wall.