You will need two 2x12x16 and have them cut into four 6ft boards and two 4ft boards.
Then take the 6ft boards and Measure from the top to 2 feet and make a mark. Then from that mark you want to Measure 1.5iches or the thickness of the board that is going to interlock with each other then go another 2 ft and then make another mark and another 1.5inch gap and then make your cuts
Step 1: Chisel Away
When you make you cuts remember that a Chopsaw cuts in a circular motion therefore you are going to be left with a Mountain like gap so you will need a Wood chisel to chisel it flat. Be carful and take you time. And if you don't know how to use one go on you YouTube and look up how to use one cuz you can destroy you project if you chisel wrong.
Step 2: Making Sure They Fit
Once you have made all you cuts, put it together and make sure everything is flush and even.
Step 3: Staining and Painting
Once you finished cutting all your pieces you can stain it or paint whichever you would like. I went with a stain because it looked a lot better.
Step 4: Support and Sturdiness
Once you have all your pieces of wood fitting correctly the way you want them to you will need to buy some brackets to add sturdiness and support. I put almost 30 brackets because I don't want to lose my tv which costs a lot more than the brackets.