That is no chair! Are you trying to make a chair that is using the same structure as this table?

There are multiple ways of making that depends up on dimensions and thickness of the door you can join the ply or block board using joint pins and use door stiffener which you get in any hardware brand you can make a frame with aluminium pipe and use MDF or less thickness material and sandwich the frame Outsource to professional door making people but make sure the inner laminate is used more than 0.9mm which majorly sometimes responsible for the bend

How to make TV wall, door mirror?

This is the picture of our new home, but it front view is looking very bad. Could you help me making it attractive and look good.