I eased into cooking with meat by buying it ground, but have since been branching out into using more and more of the whole animal.  Growing our own broilers trained me to use every bit of a chicken, and now that we've bought a whole lamb, I've been doing the same with red meat.  It turns out that there are five main categories:

Ground meat is the easiest to cook with since you can make it into burgers, sausage, or use it any other way you'd use hamburger or ground turkey.  If I hadn't asked for the front legs of our lamb to be ground up, there wouldn't have been much ground meat, though, mostly from the belly.

Steaks are cuts that are tender enough to fry or grill and eat with a knife and fork.  Both chops and sirloin can be cooked as steaks, with the latter being a bit more tender.  Our pastured lamb growers recommend searing lamb steaks over medium-high heat then finishing up cooking at a lower temperature, which worked great for us.

Roasts are cuts that are a bit tough to be fried up and should instead be either stewed over low heat or baked in a cool oven for an hour or more.  Letting them marinate first in an acidic marinate like tomatoes or wine can also help tenderize the meat.  Legs are the hind legs, cut whole and looking a bit like a ham.  Shanks are the upper arm (front leg).  Riblets are half bone and half fat and meat --- they're the only part that I'm a bit at a loss about how to cook.

Bones won't come with your lamb unless you specifically ask for them, but you should!  Bones make a wonderful broth, boiled for several hours in a pot of water.  The remains can be fed to your dog.

Heart and liver are cooked like any other organ meat.  I sometimes cook these up into broth, very occasionally fry up a liver for Mark, and sometimes give the organs to the cats and dog as a health boost.

Once you learn to cook meat in each of these categories, you'll be ready to cook nearly the whole animal of just about every type of livestock out there.  With chickens, the meat type is more a factor of age than cut, but it's still good to know how to grind or stew up old birds and to make broth out of the bones.  Even if you're not buying a whole animal, cooking with unusual cuts allows you to buy cheaper meat that is just as good for you, and to respect the meat animal by not tossing less tender parts of their body.