Map out the dimensions you need for the space you have to work with. Cut the wood planks to the basic dimensions of the full counter. Cut out a square portion of the top and front planks to the edge of the wood (leaving three inward sides) for the candy display---the countertop square should be cut slightly wider to leave room for the glass top (preferably some sort of safety glass) to rest on the inner walls of the display. Cut three smaller wood boards for the walls and floor of the candy display. Nail the bottom-most plank, the sides, the front and the top of the counter together.
Install the floor and walls of the candy display. Match the walls to the edges of the counter-front's square cutout. Cut a small hole in the display for the electrical hookup of the display lighting. Figure out where you can run a water hookup through the counter and cut three holes in the counter top---two on one side for the water and electrical hookups for the soda fountain and one on the opposing side for the popcorn machine's electrical hookup.
Cut a wood plank for the back side of the counter with three openings---one for the popcorn electrical hookup, one for the candy display and one large cut for the ice box, access to the soda fountain's water pipe, electrical hookup and carbon dioxide tank. Nail it to the counter.
Lacquer the outside surface of the counter and let it dry.
Glue the glass plating onto the top and front of the candy display case. Install the shelving brackets on the inside of the candy display and install the fluorescent light. Run the electrical cord through the hole in the display. Place the two final glass plates in the shelving brackets.
Place the popcorn machine and soda fountain on the counter and run the electric and water hookups through the counter holes. Set the cash register up to the side of the glass display case.