I have a Masterbuilt smoker that I LOVE. I smoke meat weekly, so I am getting pretty good. Ribs are the kids favorites, so we do them a lot. The secrete is low and slow. Here is what I do:
Put your favorite rub or dry seasoning on your ribs. Remove the membrane from the inside of the ribs, they are more tender when you eat them if it is gone. Place ribs in smoker and cook for 3 hours. After 3 hours, remove the ribs and wrap in heavy-duty aluminum foil (Optional: You can baste with your favorite BBQ sauce at this time). Return to smoker and cook for an additional 1- 1 ½ hours, or until internal temperature reaches 160 degrees.
My smoker has a thermometer that is awesome, however I do not typically use it with the ribs, I just go by time.
Secret to remove the membrane; grab the corner with a dry paper towel, and pull slowly. It comes off every time, the paper towel allows you to grasp it.