Do not unpack them and leave them to dry out in open air. If they must be stored, place them in the packing materials in the vegetable compartment of a refrigerator, never allowing them to freeze. Once a lily bulb dries out, or freezes, it will not grow properly. Planting lilies successfully isn't difficult. The one key point is to settle them in well-drained spots in the garden, in soil thoroughly amended with compost.
Lily bulbs are vulnerable to rotting in wet spots, so choose a place with perfect drainage.
If the drainage is poor and the area you have in mind for lilies stays soggy day after day, plant the lilies in large containers, allowing at least 2 gallons of soil for each lily. Dig at least 12 inches down, loosening the soil. Plant lily bulbs 6 to 10 inches deep, depending on the size of the bulb, putting loose fertile soil above the bulb as well as below it. It's dismaying to plunge a shovel into an apparently empty spot and come up with half a destroyed lily bulb. Lilies will bloom from early June through August.