There are many tips for cooking ribs, and for the most tender, melt-in-the-mouth meat every time, it's well worth simmering the ribs before they hit the grill.
With this two-stage cooking method, you can give the pork a more tender texture. It also gives a quicker result than cooking raw, as the ribs are already partly done.
Partially cooking the ribs in water means that some fat is removed, and the tissues soften. The water removes the skin and membrane from the ribs before they go on the grill.
Once the water is boiling, lower it to a simmer before adding the meat to avoid overcooking. The resulting meat is more likely to develop a tender texture.