Your puzzle is made out of all natural hardwood sourced here in the United States. Although a finish is not necessary, it can help to protect the wood from normal handling (mostly from dirt) and accidental spills or rain from discoloring the puzzle.
Teton Craft Works recommends at least, three products that are easy to apply and create a smooth, durable, penetrating finish.
- Tung Oil
- Danish Oil
- Bees wax
There are many videos on applying oil and wax finishes on the internet. Many of them are for finishing furniture and may be more complex than necessary for finishing your puzzle. Nonetheless, watch a few and you will get the general idea about applying these finishes.
In general, these finishes are very simple to apply, and are very difficult to mess up.