Place your plastic tub where you want your fountain to end up. Use a shovel to score the ground around the outside of the tub. Move the tub aside and dig a hole about an inch shallower and just as wide and long as your tub. If using a 24-inch-deep, 36-inch-wide, 40-inch-long tub, dig a hole 23 inches deep, 36 inches wide and 40 inches long.
Fit the tub into the hole. Place the pump in the center of the tub and tape down the electrical conduit cable along the floor and nearest side of the tub with strips of electrical tape. Connect the electrical cable to an extension cord. Don't plug the cord in yet.
Lay out your copper pipe. Screw pieces of it together, using angles and connectors to create a candelabra shape, a square spiral with short tubes sticking up at different intervals or a simple vertical pipe with tubes of different lengths sticking out horizontally from it. Play with the pipes until you make a design you like. Screw everything together tightly.
Cut a piece of window screen to fit over your tub. In this case, cut it about 42 inches wide and 46 inches long so it overlaps your tub by 6 inches on all sides. Cut a hole in the center for your central copper pipe and a 6-inch square flap in one side so you can reach inside your fountain's guts for repairs.
Thread your central copper pipe through the hole in the middle of the screen. Screw the pipe into the hole in the top of your pump. Set the pump back into the tub with the screen on top of the tub and the copper piping standing straight up in the center. Fill your tub with water through the screen's trapdoor.
Place four composite wooden boards horizontally over the screen to add extra support. Hide the screen and boards with artistically stacked piles of smooth river stones. Scatter them in a single layer or create pyramids of them over the fountain area. Plug in your pump and watch the water spray from the copper tubes.