Start by rinsing the ribs off under cold water. Pat them close to dry. Inspect the ribs and cut off anything that looks out of place. Fat hanging off, etc.
Check and see if the membrane has been taken off. It's the silver looking stuff on the underside of the ribs. I like using the back of a spoon. Get under the membrane right by the edge. Then grab a paper towel get a grip on the membrane and pull it all the way off.
You can use a food saver and seal up the ribs that way. If you can find a bag large enough, then, by all means, go that direction. I personally use a Ziplock freezer bag. Prep: Take the ribs and cut them in half and straight into the bags.
Season the ribs once you get them in the bags. You'll waste nothing this way. Zip up the bag and shake and get the seasoning all over the ribs.
Lower the bags into the water bath. The air in the bag will leave the bag from the pressure of the water. Once the air is removed, using a clip, secure the bags to the opposite end of the tub.
After 8 hours of sous vide cooking, lower the temperature to 130 degrees and cook for an additional 40 hours. Or So, you can easily do 12 hours, 18 hours, 24 hours, 36 hours, 48 hours. No problem.
To finish the ribs, place them on a roasting rack. Paint on some of your favorite BBQ sauce and place the ribs under the broiler and give the ribs a bit of texture. The caramelizing of the BBQ sauce one of the best parts. Enjoy.