Turn the main water shutoff valve 90 degrees clockwise.
Clean the end of the pipe to which you want to add the two-way diverter, using a moist cloth if the material is CPVC or PEX. If the material is copper, rub a fine-grit sandpaper over the end of the pipe until the surface is shiny. This will create a clean surface for the diverter.
Place one end of the diverter over the supply pipe. Push down hard on the fitting until it snaps into place. The fitting should move about 1.5 inches down the pipe before stopping. There is no need to add solder or plumber's paste to the connection, as the compression fitting will automatically grab the pipe.
Push two sections of new pipe into the other ends of the diverter until they snap into place. Copper, CPVC and PEX pipe can all be used with the diverter.