Bath plug and washer:
If placing a bath above a concrete floor you can use a two-part plug and washer waste fitting. Measure the two centers off the wall to the center of the bath waste hole and transfer these measurements onto the concrete floor. This is the marks where the new bath trap will rise up and out of the concrete. Also you will need to use either an adjustable height extender trap or measure the height from the floor up to the lip of the male bath plug and washer and place the trap accordingly in at this height.
With this trap positioned correctly later on it is just a matter of sliding the bath into place with the bottom half of the plug and washer waste in position above the trap and then with the top hole of the bath lined up silicone in and screw the long connecting screw into place and tighten.