Step 1: Mount the Shower-Tub Unit

With a couple of helpers, set the unit in proper position and check to make sure that it is plumb and level.

Use wooden shims to adjust the unit as necessary.

Secure the unit to the wall with screws.

Courtesy of James Calloway

Step 2: Prep for Plumbing Fixtures

To prepare for the installation of the spout and knob unit that controls the diverter valve, which turns the water on and off for the showerhead, draw a perpendicular line down the center of the back of the tub to denote the center of the tub.

Draw a horizontal line across this line at the best height to allow the spout to sit one inch above the top of the tub, as required by many building codes. Above the spout, mark the placement for the diverter.

Drill pilot holes from the back of the tub as starter holes to mark the placement of the spout and diverter.

Use a hole saw to cut the appropriate size holes from the front of the tub. Hole saws are available at most rental-supply centers.

Step 3: Install the Diverter

Wrap plumber's tape (Teflon tape) around the threads of the copper fittings and install them in the diverter.

Snap the plastic support piece onto the diverter and fit the diverter assembly through the back of the tub. Secure the diverter by fastening the escutcheon plate from the front of the tub.

Cut a pipe to connect the bottom of the diverter to the spout. When you make your measurement, subtract one inch to compensate for the size of the fittings