Cut the bottom cup holder board to size and drill 3/4" pocket holes along one edge and both ends. Attach it to the bottom of the frame with 3/4" pocket hole screws and wood glue.
Cut the side cup holder pieces to size and attach them to the bottom of the frame and the bottom of the cup holder with 1 1/4" pocket hole screws and wood glue. The backof the side pieces should be flush with the back of the dry erase board.
Cut the front cup holder piece to size and attach it to the side and bottom cup holder pieces with 1 1/4" brad nails and wood glue.