Welcome back glad you re-joined us. The 3-2-1 method is for spare ribs with the smoker at 225*. Smoke the ribs for 3 hours then into foil for 2 hours then back into the smoker un-foiled for 1 hour. This method is a general guideline and will give you tender fall off the bone ribs most people will modify it with experience to get to what suits there preferences and tastes.
For baby back ribs try 2-2-1