This is a classic recipe, easy to do in a crock pot or slow cooker. This may also work fine in a covered pot in the oven, or even on a stove top.
First, buy several bulbs of garlic.
Next, use around three or four pounds of lesser chicken parts-- thighs with bone in, and skin, work well.
Boneless skinless chicken breasts are wasted on this dish, they won't taste as great.
It's not necessary, but, if you feel like it, you might braze or brown the chicken parts first, using a little oil and flour in a large frying pan. Put some diced onions in there. Possibly a little celery, maybe a diced carrot. The garlic could be cut and peeled, but it doesn't need to be, except for cutting off the root end base. Some recipes don't peel the garlic. Separating the cloves, cutting the root end and peeling off the dry shell produces a good result. It takes three or four garlic bulbs to get 40 cloves. Using chicken parts with bone in seems to work well; thighs, bone in, work, breasts work OK but may not be quite as juicy and tasty. Add some seasoning. Not everyone cares for rosemary, so possibly use thyme, or just a little pepper or some seasoning mix like Mrs Dash. After cooking a while add a little salt.
Before serving cooked meats it's a good idea to take a chunk of the meat and slice it to check for any pinkness. Be sure the meat is at least cooked, and hopefully not overcooked.