The most important part of soup, and many other dishes is stock. There are three main ways of making stocks that involve animal bones.
The first involves poaching whole chickens until the meat reaches 155 degrees F, removing the chicken and reducing the stock. That’s it, just chicken and water.
If you have bones, from the butcher or from deboning an animal yourself, you have two options:
roasting them then making stock
making stock without roasting them
Either way you need an ample amount of bones–also feet in the case of chickens, anything with cartilage and connective tissue in all cases–cold water, and aromatics. Many people feel the basic aromatics involve mirepoix (onion, carrots, and celery) along with bay leaf, black peppercorns, thyme and/or parsley stems, and whole garlic cloves (ideally wrapped in cheese cloth for easy removal). Stock must be simmered (you should see what is referred to as champagne bubbles rising to the top) for several hours to extract the best flavor, then strained.
You can also add or remove any of those ingredients. I’ve known chefs who think carrots make the stock too sweet and adding parmesan rinds adds more umami. There are many variations to making stock, but the most important part is cooking it slow and low and NEVER ADDING SALT. You add salt when you’re making your dish.
Once you’re made your stock and strained it you can make a double stock, by going through the whole process again using your already made stock instead of water, or reducing the stock you have to make it richer. I highly recommend going crazy and making a huge batch of stock, reducing it to a third of it’s original volume and freezing it in ice cube trays. It’s a long process, but you’ll be really thankful next time you make dinner!