look at the examples and you will see some great examples.
my personal favorite way is to cut a circle out of plywood and mount the monitor in it.
Then add an area that the board will lean against. So it will be at a slight angle (weight going mainly down, but some back.
On the back board (that your circle is sitting on) will have wheels around the edges holding it forward.
Then on the bottom and a few on the sides will hold it up and in place.
As for rotation itself. Have a cord wrapped around the center (add some nails or screws in a circular pattern around the monitor)... And have one side at the top left of your cabinet, wrap around the monitor / wheel, and out the other side of the cabinet.
btw, I've heard from many that adding rotating monitor support will take longer then the rest of the cabinet...
good luck