I put them in a roasting pan with an inch of water in it and the ribs on a wire rack to keep them above the liquid. Tightly seal with foil to keep the moisture in. 120C fan oven for 3-4 hours. You can pile them up / I often cook 2 or 3 roes worth at a time in a big stack (4-6 sides of ribs)
Once done, I drain the liquid to use for stock. Quick rinse of the pan and line it with the foil I used to seal it during slow cook.
Over up to 190c fan and slather ribs in bbq sauce. 15-20 minutes.
Napkins and finger bowls/ wet wipes a good idea.
On this occasion I only needed 2 sides of ribs but cooked 4. Two were left to cool after slow cooking then stripped from the bones and frozen. Make good sliders/ sloppy joes/ wraps etc etc.