Click on HSL in the HSL/Color/B & W panel. It isn't 20 colors. There are 8 color ranges and you can control those ranges with hue, saturation, and color.
There are eight color ranges. And they are divided into three areas, hue, saturation, and luminance. You have them highlighted in your illustration. Is that screenshot taken from the tutorial? If it is, then you need to click on HSL as I have illustrated here:
It is one of the panels on the right-hand side of the develop module. If you don't see that panel then you need to press Ctrl/3 (Cmd/3 Mac) Or go to the Window->Panels to see the options for showing the different panels. As you can see from my illustration, the eight color ranges are red, orange, yellow, green, aqua, blue, purple and magenta. And you have three areas where you can control those colors. But there are not 20 different hues that you can control.
And, just for clarification, this is where the HSL panel displays in the right-hand panel of the develop module:
But since this is the Camera Raw forum, I'm wondering if you are expecting to see that same display in Camera Raw. It's noticeably different:
In Camera Raw these controls are accessed by clicking on the little icon I have highlighted, and then the controls are distributed among three different tabs.
Thanks for taking the time to help me, Jim. I see now that what I thought (tut wasn't sharp and I couldn't read color names) were 24 colors were only 8. I appreciate your patience, Jim. It was pilot error on my part.