Try the steps below to resolve your issue.
You want to dig a shallow, broad planting hole about 2-3 times wider than the root ball, but only as deep as the root ball. Make sure you unwrap the plastic or burlap from the root ball and place the tree in the hole by the root ball, not the trunk. Fill it in slowly, but firmly. Pack the soil around the root ball to stabilize it. Watering periodically while backfilling will help eliminate any air pockets. Then you want to mulch the base of the tree about 2-3 inches deep. This helps retain moisture from rain and watering. Watch this helpful video from the EPB Energy Pros for more information.