You need to study in Outland's Hellfire Peninsula. The alliance is in the honor castle and the tribe is in Salma. Take the tribe as an example. The way to find a trainer is as follows:

1. First, players need to come to the map of Hellfire Peninsula in Outland.

2. Then come to Salma's camp.

3. Then come to the vicinity of coordinates (57, 38) and you can see the jewelry processor.

4. Click on the dialogue to learn the jewelry processing formula with more than 300 skill points.