Congrats on the new toy! You have more options with a Pellet Grill because they have a greater temp range than many smokers. Depending on the exact cut of Beef Ribs you have, the timing will vary. Beef Side Ribs, meat between bones but little to none on top, can be smoked in a similar manner to Pork Spare ribs. A common method for nearly Fall of The Bone is 3-2-1. Three hours of Smoke at around 225°F followed by two hours wrapped in Foil with a flavorful liquid. In the case of Beef, some Beef Broth with any combination of Wine, Beer, Worcestershire Sauce and some of you Rub, 1/4 to 1/2 Cup per Rack, is a good choice. This is followed by 1 hour or so, unwrapped, back on the Smoker Rack to finish the cook and get a nice Bark on the ribs. This is the time to added any additional Sauce you might like. All this happens at 225°F. For Beef Short Ribs, there is a thick layer of meat on top of the rib bones, An extended time in the Foil with liquid is needed to tenderize the meat. This can be 3-4 hours rather than 2. A good test is to take a Therm Probe and stick it in the meat in a few places. If the probe slides in with little to no resistance you can unwrap and set the bark.
As I said, the above procedure happens at around 225°F. The benefit of your Pellet Grill is you can save time in the Middle Stage by bumping the Grill temp to 325-350°F. This Braise of the beef can cut the Foil time in half, give or take. Your grill will make very little Smoke at this temp but, hey the meat is in Foil and no smoke is needed anyway. Again the probe test is your best gauge of tenderness. Reduce the heat below 300°F for the last phase to avoid burning any sauce you add the last hour. Good Luck and feel free to post any more questions...JJ