Oh dear, 6 x 4 feet? You might have been better choosing something else, but keeping it in a pot might be the way to go, though not sure how well it will respond to being contained. This one is said not to be as rampant as the more common Russian Vine, but nonetheless, if planted in open ground, it appears it will reach 25 feet by 25 feet as a minimum, unless a cold winter checks it - it's not quite as hardy as Russian Vine either. Certainly a position on a southfacing or sunny fence out of cold winds will give it the best chance, I'd imagine, but all you can do now, if you have already bought the plant, is pot it up and see what happens. Will need regular potting on, ending up in the biggest pot you can provide for it, say a minimum of 2 feet deep by 12 inches across.