Measure the height between the floor and the bottom of the cabinet.
Measure the length of the gap at the bottom of the cabinet.
Mark on a piece of 1/4 inch plywood the two measurements of the cabinet gap. Measure twice and cut once.
Cut the toe kick to length with a circular saw.
Place the toe kick underneath the cabinet. Use a scribe to take off small amounts of wood if the toe kick does not fit properly.
Attach the toe kicks with finishing nails.
Insert a tube of caulk into a caulk gun and cut off the tip. Apply a thin bead of caulk along the gap between the cabinet and the toe kick to finish the project.