Measure the width of the door that is to receive the kickplate with the 12-foot steel tape measure. Subtract 1 inch from the width to allow 1/2 inch on each side that will not be covered by the kickplate.
Lay the kickplate on a clean flat surface, such as a workbench. Measure and mark the desired width on the kickplate with the 12-foot steel tape measure and the pencil at the top and bottom of the kickplate.
Place chalkline on the marks, pull tight and snap making a line across the kickplate.
Use the hacksaw to cut smoothly and evenly down the line. Take your time and go slow to avoid burrs and rough edges.
File away any rough edges with the flat file.