Bathroom renovation, I need assistance with new concrete floors, waterproofing/membrane and tiling on floors and walls

I´m renovating my entire bathroom. i will be doing some tasks myself, but i need assistance on some tasks. My friend (rørlegger) and i will: - remove existing fittings and fixtures - demolish the tiles and dry wall from the walls - remove the existing concrete floor/membrane etc. - lay the new warming cables (at the appropriate time) - organise the electrics What i need from you: - New concrete floor - Relevant waterproofing / membrane to Norwegian approved standards - Install new dry wall - Install new tiles on walls and floor - Build a small box for a hanging toilet Once you have finished your part, my friend and i will come back in and install the toilet, sink, shower, mirrors, lighting etc. The room is approx 2. 2m x 2. 2m x 2. 4m. i will buy all tiles and provide them in the house