It is best to plant the trees as soon as possible after you pick them up. In the meantime keep the trees.
Cool & Moist
Cool: A tree's survival is reduced if they start growing before being planted. To prevent growth keep the trees cool. The best temperature is 34°F. Do not stack bundles of trees. Considerable heat can be generated by the pressure on the lower trees.
Moist: Do not soak the trees in a bucket of water! This can cause roots to rot. The roots are dipped in a polymer gel to help retain moisture. If the trees will be planted within 2 days they should remain moist if they are left in the bag you received them in. You will need to sprinkle water on the roots or add wet newspaper or burlap to the bag if you do not plant within 2 days.
Planting: When planting trees depth of the hole and repacking the soil are critical to a tree's survival.
Depth: The hole should be deep enough to prevent the roots from curling or bunching. Plant the trees slightly deeper than what they were planted at the nursery. A soil line can be determined by finding the point on the trunk that has a change in coloration and slight swelling. Be sure to plant the tree in an upright position.
Repacking: It's important to avoid air pockets around the roots. Air will cause the roots to dry out and the tree will die. Be sure to firmly pack soil around the roots. Stomping on the soil may cause root damage - use common sense when packing the soil. If possible water the tree after planting to further ensure that the roots are moist and soil will settle into any small air pockets.