Mark out an area about 1 meter square and plant 3-4 kernels of corn in the middle and cover it with 1 inch of soil.
When the corn sprouts, start mounding the soil over the base of the plant (don't cover it completely though!) Do NOT thin the corn. You want two or three stalks per mound.
Two weeks after planting the corn, plant two or three pole bean seeds in the mound. (If possible, coat the beans with a legume specific bacterial innoculant to insure the bacteria will be present. You can order it with seeds online or maybe get some at a garden center.) At the same time as the beans, plant squash, pumpkins, or other vining squash around the mounds.
That is it. Then just follow the care instructions on the vegetable seed packets.
What happens is that the corn stocks support the beans, and the corn roots ooze a sugar that the nitrogen fixing bacteria on the beans love. The bacteria feed the beans corn, and the squash. The squash shades the ground around the corn, keeping it cool, moist, and (relatively) weed free.
