Now that you have two identical 2X4s cut, you are ready to layout where your "studs" need to go. You will want to mark both the bottom and the top plate the exact same. Make a mark with your pencil on both plates every sixteen inches. Square the lines across the 2X4.
Now you will need to decide how tall you want your bar to be. For me, I chose 4 feet tall. Doing some basic math 48"- 3" (for the top and bottom plates) - 3/4 " ( thickness of MDF board) = 44-1/4" <---- This will be the cut for the "studs". Make as many cuts you need to satisfy all the marks you made on your top and bottom plates.
Once you have made enough "studs" you will now need to screw these studs between the top and bottom plates. Make sure that the studs are lines up with the lines you made across the plates.