Remove the existing tile baseboards. To do this you will need to use a putty knife to remove the grout. After the grout is gone, slide the putty knife behind the tile baseboard and move it back and forth until the tile is loose. Remove the tile. Repeat with all of the tiles.
Remove any debris from the tiles. Vacuum the area.
Measure the wall where you are installing the baseboards with a measuring tape. Use the measurement to mark the baseboard to size.
Place the baseboard on the miter saw. Cut the baseboard to size. Set the saw to a 90-degree angle for straight cuts and a 45-degree angle for corner angled cuts.
Nail the baseboards into place on the wall with a pneumatic nail gun.
Paint the baseboards as desired.