Great tutorial dice!
I learned it a bit different:
1. My dogs already knew to touch a post-it on command so I let them touch a post-it that was under a empty glass bowl (that they could see through the glass), so they would actually touch the bottom of the bowl
2. When the dogs got the idea I removed the post-it and let them touch the bottom without the post-it
3. Then I filled the bowl with water and asked the behavior (I filled it completely at once, since otherwise my dogs would just drink from it, but I would recommand first starting with a little bit of water and adding more step by step)
With this step I first clicked for just touching the water, later for putting their nose in the water and finally blowing bubbles.