The bare roots should be soaked from an hour to overnight (large plants) in a bucket of water before planting. Trim roots of broken, dead, or spongy bits and carefully pull the roots apart. Dig a hole that is fairly shallow and wide. Spread the roots out sideways and have the crown of the plant several inches above the soil level. This is necessary as the plant will settle down over time. Water in well but wait to fertilize until you see new shoots growing. Be sure to water regularly if the rains are sparse. Staking may not be necessary.
Trees aren't the only plants that are sold bare root. You can also plant bare-root asparagus, artichokes, rhubarb, berries, kiwifruit, horseradish, rhubarb, grapes, roses, strawberries, and iris in January.
More information: Planting Bare-Root Fruit Trees