I started Phoenix about a month and a half ago on nose work. We haven't gone to any classes and I only read a little bit about how to train it. I did this completely on my own and it might be "wrong" but she definitely understands that she's supposed to find a specific scent. I began collecting plastic containers a while ago and ended up with some matching daisy sour cream containers. I cleaned them really well and cut some holes in the lids. The container with the active scent has the lid with the most holes.
To start, I put the scent in the container and let her sniff it. Click treat. I repeated this over and over until she was only sniffing the container. We did have some trouble with other behaviors popping up because I wanted to shape this and previously I had been shaping retrieves and playing 101 things to do with a box. So I didn't want her pouncing on the cup, or bringing it back. So it took a while for her to understand she was only supposed to smell it. Then I added more containers (one at a time) with no scent and started clicking her when she found the correct one.
Here's a video:
In the video I'm just starting to add the cue and then realized that "seek" sounds too much like "speak". So I will change it to something else.