Unwrap the box as soon as possible. The roots' surface have been dried before shipping to prevent rot. Soak the roots in tepid water for 3 or 4 hours before planting. The tops have been trimmed for shipping but they'll recover quickly after planting.
If you're unable to plant soon after receipt keep the plants in a cool dark location. after you've let the surface of the roots dry out again. A paper bag in the refrigerator will do for a few days....but don't let them freeze.