A: You should always season a new cedar lined humidor. Even if you are using crystals, the dry wood will suck away all the moisture. How much water you need depends on the size of the crystals. As a general rule of thumb, you should add enough distilled water so that the crystals can fully expand to the limit of their container. Avoid allowing the crystals to expand beyond this, is a big no-no (can make quite a mess). Slowly add water and allow time for the crystals to absorb it all. Do this until the crystals have fully expanded.
A: Just simply add distilled water by pouring it slowly through the cracks. You want it saturated but not dripping. Once it's full, drain off any excess and use the magnet to mount anywhere in the humidor. You can also use cigar juice for more stable humidity (less often fills, less variance/spikes).