Most smokers will have two dampers, one at the top and one near the firebox. It may take a few tries to get to know your smoker but practice makes perfect. In general, you want to ease the smoker into the temperature you want. Remember, the more airflow the hotter your wood or coals will burn. When you get about 50 degrees from where you want the smoker close the dampers almost all the way until there is just a little airflow. From there monitor the smoker every thirty minutes or so adjusting the dampers as needed.