Read the installation instructions for the wooden stove that you are installing to determine the minimum wall clearance required for the stove. Place a tape measure at any nearby walls to determine the clearance and mark the locations using pieces of tape. If you are installing the hearth in an open area, measuring is not required.
Place the purchased hearth pad on the floor, making sure it is aligned with the tape lines, if applicable. Cut around the perimeter of the hearth pad if the underlying floor is carpeted. If there is padding underneath the carpet, cut it out as well. Cutting out the carpet is required to prevent fires.
Place the wood stove onto the center of the hearth pad. Place the end of a tape measure at the front of the wood stove and measure out from the stove 8 inches. Place a piece of tape on the hearth in this location, which is where the front of the hearth pad must be. If there is not 8 inches of space, move the stove back on the hearth until there is.
Move the tape measure to the loading side of the stove, where the door is, and measure out 16 inches. If there is not 16 inches of space, move the stove in the opposite direction until there is.
Repeat the measuring process on the opposite side of the stove, but reduce the measurement to 8 inches. If there is not 8 inches of space, you need a larger hearth pad, since you have already set the other side to the appropriate clearance.
Remove any remaining tape from the floor and hook up the stove using the manufacturer's instructions.