Before you begin the seasoning process, make sure to read any directions that may have come with your new humidor. Always follow the manufacturer's instructions so you do not void your warranty. Absent any specific instructions from the manufacturer of the humidor, proceed as follows.
To season a humidor, all you need is some distilled water, a clean unscented sponge or cloth, and some patience - at least for a few days. IMPORTANT - Do not use tap water in place of distilled water.
Start by dampening a clean sponge or cloth with distilled water, then wipe down all the cedar wood inside of the humidor, including the lid and any trays. To avoid damaging the humidor, do not overly saturate the interior wood with water. Do NOT spill the water inside the humidor (and then try to spread it around).