One of the dials controls pressure from the thin brass tube leading to the burner.
one question. One of the dials controls pressure from the thin brass tube leading to the burner. When and what is this used for?
The right valve is controlling gas to the thin copper tube as the pilot flame. You can turn off the main burner between dishes if the pilot flame is lit. We have a video (2nd one) on page http://outdoorstirfry.com/?page_id=768 on how to light the pilot flame. Alternately you can choose not to use the pilot at all by turning the main burner really low between dishes.