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.