This kit is designed to be started immediately, a short delay of a week or two is OK, a delay of a month or more is to long and not a good idea. It may still grow, but fewer mushrooms will be produced the longer you wait . If you wish to delay, starting your kit for a few weeks, store the kit in a cool location below 50 degrees F and above freezing. Open the bag of compost, and pull up the excess plastic bag and leave it pointing up in the air, if it does not stay up tape it to the box flaps. Inside the bag of compost is a small bag of dry peat moss mixed with a little calcium carbonate, this is called casing.
Casing is used as a covering to hold water and protect the mushroom mycelium growing in the compost.
You can use a nail or fork to do this. Let the casing sit in its' own bag for 10 minutes to absorb most of the water before applying it to the compost. When made correctly you should be able to squeeze water out of the casing like a saturated wet sponge. Do not pack the casing down, leave it loose and fluffy. The casing should cover all the compost, and be approximately 1 inch deep.