All piping should be installed before installing the tub itself.

Lower the tub into place. This will allow a continuous flange to fit against the wall studs and rests on 1 x 4 or 2 x 4 supports. In relation to this, don’t forget to anchor the tub to the enclosure with nails or screws ensconced through the flanges into the studs.

Put together the drain connections. This can be done by way of attaching the tub overflow with the tub drain above the trap, and not beyond it. Note that the trap will have a compression fitting that screw over the arm of the overflow assembly.

Run the hot and cold water lines to the tub or shower mixing valve where they are attached. You can do this by sweating these directly into the hot and cold ports of the mixing valve.

Run a pipe up the wall for the shower head. Note however that on the top of this pipe, you should sweat on a brass female threaded winged fitting that is nailed or screwed into a framing support.

A piece of 1/2" pipe should be extended, but this must be in accordance to the instructions provided by the manufacturer, for the tub spout. Also sweat on a male threaded fitting at the end of the pipe or employ a brass nipple of the proper length as well as a 1/2" cap.

At this time, you will need to have your rough plumbing checked.

Restore water pressure and inspect the drain connection, including the supply pipes for any leaks.

Replace the wall with moisture resistant drywall as a base for your wall covering. Also important to note is to seal joints between the wall and your new tub perhaps with silicone caulk. This caulk will serve as protection against water seepage.

It is now time to install the handles, shower head and Spout. Note that the shower head screws onto the shower arm stub out. And, whether you are installing a new shower head or replacing an old one, always clean the pipe threads and apply a new pipe joint compound. You can also consider a Teflon tape or both to prevent leaks.

Master Faucet Products Installation Guide