Example below: The wires need to run up behind the wall to the ceiling (see image below). A return was created between two existing walls (you will need to create two columns) - through which you can run the wires if necessary. The screen is hidden in the beam above the painting. In the foreground of the photo is another "beam" which actually contains the projector. It has an access panel again covered in the mesh and there is a flap that can be removed or opened/closed when the projector is in use. US is way more advanced, so I believe other Houzzers can step in...

HI -- Well this is a nice floor plan but it creates problems . Because the space is all open doesn't mean you have to put the living room or the dining room where indicated on the plan . Also where you have marked for the sofa is not going to work there . Not enough room and in the way of getting to the bathroom etc, I do think you may have to have a free floating TV stand between the living -dining rooms . You could have the TV on the wall beside the kitchen and have the sofa facing or on the left wall and the dining at the front . I would put the TV on the left wall near the entrance and have the sofa facing it , leaving a hallway walking space behind the sofa . It's too bad the front entrance is on the left . If it had been on the right then that would be better flow into the center of the main floor . If you do decide to have the TV room divider where you show on the plan , keep it right over to the left wall as a room divider , then it won't cut the room in half so much and it keeps the stairwell open . Remember , you do not need to push the furniture against the walls .

You can also think on panel work with some openable shutters which can hide the boards as well give an access to use when needed . Bottom can be a sleek storage with louvers where inverter can get tucked in and also a seat or a ledge used for multipurpose. One thing to remember this set out would not be budgeted but, can allow you to explore option to make it look good or articulate well.

While doing your electrical works during the interior works you can put conduit from tv to music system.