If you are unable to plant right away, then All plants should be kept in the shade ( even sun plants ) and the roots kept covered and moist, until they are planted.

Planting & Watering Instructions
Be sure to select appropriate location for your plant. ie ; place sun plants in the sun, shade plants in the shade etc.

STEP 1: Prepare planting hole
Dig a hole twice as wide as the root ball.

STEP 2: Planting
Place plant in the hole then backfill the sides with a mixture of 1/2 soil from the hole and 1/2 potting soil ( best to use a high quality soil such as miracle grow or scotts ) . Tamp the soil firmly around the root ball.

STEP 3: Finishing
Fertilize with Osmocote ( or similar ) slow release fertilizer. ( best to use fertilizer with 6-10 month time release )
Cover with a 1-2" layer of mulch over the root ball and over the rest of the planting area. Keep mulch 2-3 inches away from the trunk or stem.

WATER WATER WATER, as described below

Immediately after planting
When you've completed the planting process, water your new plants thoroughly. Use a watering wand or something similar running at moderate pressure - . A thorough soaking will take from 10 seconds for small plants to 1-2 minutes for larger shrubs and trees. see chart below

Starter plants and Quart size plants : water for 10-20 seconds per plant
1 to 2 gallon plants : 30-40 seconds per plant
3 to 5 gallon plants or larger : 1-2 minutes per plant

Water 1 to 3 times a week for the first year, then as needed depending on weather
( plants may require more water during the hot summer months, possibly once daily until established. )