After digging an appropriately sized hole for the tree, carefully lower the tree into the hole. Then begin to backfill with the original soil. When the planting hole is one-half full, cut and remove all twine. Also, cut away and remove the burlap and wire basket on the top one-third to one-half of the rootball. Then fill the remainder of the hole with soil.
Learn more about planting balled and burlapped (B&B) trees in this article: Tree Planting Basics