What does nose work look like?
The final picture looks a lot like the work done by working detection dogs, such as those finding narcotics, explosives, forbidden foods at airports, or sea turtle nests on beaches.
You, the owner, will determine the area that your dog will be searching in - for example, one room of your house, your garage, your yard, or a particular area of the park. Your dog may be off leash if it’s safe, or on leash in public. You give them their cue, and they go off to find the “hide” using their excellent sense of smell, then indicate its location by pointing at it with their nose, staring at it, sitting and looking at you, or another signal you’ve trained.
A dog can be trained to find many different scents. In lieu of the essential oils used in competition, you could use a spice or extract (one that you don’t normally use in your kitchen, so your dog doesn’t get confused when you’re cooking), a dog toy, or an object (such as your keys!). You can even just use their kibble or treats, especially at the beginning.
Here’s a video from AKC that explains the sport and shows dogs practicing. (Note that while the video mentions that dogs must be registered with the AKC in order to compete, it is NOT limited to purebreds. AKC provides a way to register mixed breeds so that they can compete in nose work and some other AKC sports.)
Here’s another video with examples of typical of K9 Nose Work training.