To create a new tool, click the button at the top of the list:
To show the actions associated with a tool, click the (menu) icon on its top-right corner:
These are the actions available for a tool:
Tools can be reordered by dragging their top handle (as for Color schemes)
Most of the tools are divided into two sections: Input and Output.
In the Input section, you decide what color(s)/image the tool will work with. In most cases, you can also specify some options, for example what color space you want to work in, how many colors to generate, if to equalize the lightness in the output, and so on.
The Output section contains, for most of the tools, the color scheme(s) it generated, or some other kind of result. Color schemes in output have two actions associated: