Start a wood or coal fire in your stove, and then open the door to the stove slightly.
Adjust the knurled knob located on the front of the damper vane counterclockwise to reduce draft or clockwise to increase draft. While adjusting, the fire should not die and the fire should not produce excessive smoke.
Test the temperature of the vent stack between the stove and the barometric regulator, using the thermometer. The temperature should be 350 to 450 degrees F. To increase the temperature, adjust the knurled knob clockwise. To decrease the temperature, turn it counterclockwise.
Tighten the jamb nut on the knurled knob with a wrench, to lock the knob in place.
Close the door on your stove.