I know for cigars to be stored properly they must be placed in a humidor. Do I need to do anything to the humidor beforehand?
Yes, you must "season" the humidor.
It's a different method of seasoning, of course. (Humidors don't perform well when filled with oil and put over an open flame.) But the wood interior of the humidor needs to absorb humidity before it can become the ideal home for your cigars. Here's what to do.
With a new sponge—unscented, free of soap and liberally dosed with distilled water—wipe down all exposed wood, including any trays and dividers, as well as the interior lid. Avoid using a paper towel or a fraying cloth; these will literally leave a paper trail on the wood. After you've wet the wood, squirt the sponge with more distilled water, then place it inside the humidor on a plastic bag (to avoid contact with the wood) and close the lid.
Next, prepare your humidification device according to the manufacturer's instructions. Unless the manufacturer specifically states that you can use tap water, use only distilled water. Tap water contains minerals that will destroy most humidification systems by leaving deposits that will clog the humidor element. Once the humidification element is filled, be sure to wipe it down to remove all the excess water. Rest it on a hand towel for approximately 30 minutes.
Add the humidifying element to the humidor and close the lid, leaving the damp sponge inside, and leave it overnight. The next day, refresh the humidification device if it needs more water, and check the sponge. If it is fairly dry, add more distilled water. If it is very damp, leave it alone.
Let the humidor sit another night, then remove the sponge and plastic bag. The walls of the humidor have now absorbed all the water they need, and you can safely add cigars.