Once home, I'm ready to decorate--but not before recutting the trunk about 1 inch above the butt end to aid in water absorption. If you don't have a saw, most places will do this for you. Get your tree into a bucket of water within an hour of cutting, or the pores will seal and your effort will be in vain.
If the tree is fresh-cut from a farm, then go ahead and put it in the stand. Otherwise, soak it in a bucket of water outside overnight. I like to spray mine down with a hose to remove debris and help hydrate the needles.