I'll just jump in with both legs, here is what I have so far. I am open for criticism.
Note: There might be some spelling errors, english is not my first language. I'll proof-read when the content is complete.
Why?
The reason your humidor needs to be seasoned is to get it ready for use, meaning receiving cigars. When seasoning; the wood inside is saturated with moisture, so that it no longer is hygroscopic. Putting cigars in an un-seasoned humidor would cause it to steal humidity from the cigars, which is not the intended mode of operation.
When?
A humidor needs to be seasoned:
• Before first use.
• After a period of no or very limited use.
• If the humidity cannot be maintained at a satisfying level.
Therefore, you might only need to season it once, or multiple times. Depending on how well it is maintained and how you use it.
How?
There are many ways to season a humidor, and how you do it boils down to personal preference. You will need:
• An accurate hygrometer; these can be calibrated using the salt test.
• Distilled or sterile water. In some countries distilled water can be hard to get. In that case, sterile water, found at drugstores, can be used instead.
• A cloth or shallow dish.
• Patience.
Empty your humidor before starting, zip-lock bags or Tupperware boxes makes acceptable temporary storage. Put a Boveda pack or similar humidifier in the bag or box to be on the safe side. Place somewhere dark.
Some prefer to wipe down the interior with distilled or sterile water; use a new cloth and make sure not to use too much water. The wood should only slightly change color. Another method is to put a shallow dish with distilled or sterile water in the humidor and let it set.
In both cases leave all trays, drawers, separators etc. made of wood in the humidor, so these get seasoned as well.
Make sure you have an accurate hygrometer, that can be trusted, inside. So you can monitor the progress. Leave the humidifier and close the humidor.
After 24 hours open and check the humidity levels, if you wiped it down you may need to redo this depending on the humidity. Or make sure what there still is water in the dish if you used that. Close and leave closed for another 24 hours.
Redo this until you are satisfied with the humidity level. If so remove the dish, if present. It is now important that the humidor stabilized before adding your cigars. This may take a few days. Check the humidity regularly.
When the humidor is stable and it's time to add your cigars, do so in batches. Adding them all at once might throw off the humidity levels again. Allow for the humidor to stabilize again before adding the next batch.