I start with all the bones and carcass from a meal of roast chicken, put them in a crock pot, fill it with water and add a glug or two of apple cider vinegar. (Any vinegar will work.) I turn it on high until it boils, then turn it down to low for 24-48 hours. I add water as needed. Strain it into mason jars for pressure canning or freeze them like I do--leaving at least 1 full inch of head space.
I feed the mushy bones etc to my pups or to the chickens...the dogs hang around the kitchen during the broth making. They LOVE the bones and they are safe to feed to dogs b/c they literally mush in your hands.
eta: you don't need to season it, the flavors get weird after so many hours in the crock pot. Season your broth after it is made.
You can use any raw bones, too.
I have done pork, turkey and chicken. Turkey and chicken bones take around 24 hours in my slow cooker, the pork neck bones take about 48 hours. I haven't had any beef bones for some time now, but one of these days... The bone broth is terrific! So much richer than plain stock.
I browned the pork neckbones in the oven, then cooked them on the stove with some water. I picked off as much meat as I could and put the meat and broth in quart jars for us. Then I froze everything and make bone broth as I feel like it with the leftover bones.