Adjust the bones and water according to your goals and stock pot size, in generally equal proportions. Roasting bones for 20-30 minutes in 425-450 degree oven adds some richness to the stock, and roasting the vegetables with the bones adds even more richness. Important to note that simmering the stock is important from the start and never allow it to come to boil, which clouds the broth and alters the flavor. Keep it low and slow.
If roasting bones, deglaze the roasting pan with water to scrape up bits and flavors and pour into stock pot with all other ingredients. All ingredients to the pot after roasting, then set flame to medium low and watch for the pot to come to temperature. Low simmer is the goal. 6-8 hours on low simmer. Skim any foam. Keep bones covered with fresh water if too much evaporation.
At end of simmer, strain all liquid from solids and put pot into refrigerator overnight. Skim any surface solids in the morning, and divide amongst containers. Freezes well. You should have gelatin, which is the gold (some people, like my mother, thought this meant it went bad…not the case!).