Thank you to Adrian for the work! This area was originally a bath room which was converted to a wet room. The room was completely cleared before work commenced.
To create the form in the floor nowadays is simpler. You can purchase ready made fibre glass shower formers which have the pipework and drain already fitted .
The floor in the corner of the room needed to be dug out lower than existing concrete and pipe work fitted. The former would fit inside the hole.
The floors would then be latexed and allowed to dry before the new vinyl safety flooring is laid.
Be aware many times people have installed the wrong drain for vinyl wet room flooring make sure its round and has a collar inside usually held in with 3 large screws. This collar holds the vinyl inside the drain making sure no water goes back up and under the vinyl.