If you are replacing a section of already installed carpet just pull it back far enough so that plenty of the undersides are exposed.
Carpet seam tape installation.
Position the seaming iron.
Place a carpet seaming iron under the two pieces of carpet against the carpet seam tape and plug in the iron.
Carpet tape does make it possible to install multiple pieces of carpeting side by side and if you follow directions for installing carpet seam tape seams should blend with the rest of the flooring.
When the carpet is stretched it is pulled where the edges of the tape are attached to the carpet and the two pieces lift to create a peak.
Depending on the type of tape you use you might need to heat it for several minutes to begin activating the adhesive on the seam tape.