To start the Agave program click Applications menu, Choose Graphics > Agave You will see a window like the following. Next you must choose a color, there are two methods to pick a color, either click on the button that will bring up a dialog. Using the eyedropper tool you can choose a color. The 2nd method is to select a base color by using the color palette located at the bottom part of the window. Now to add your own custom palette. You must first create a palette file. In my example is the format to create your custom palette: All palette files must start with the GIMP Palette header and a palette name. You can optionally include a comment starting with a #. The remaining lines define individual colors' red, green, and blue components ranging from 0 to 255. Your palette file should be saved with a .gpl extension and saved in home directory at /home/example/.local/share/agave/palettes/. If your file is well-formed, Agave will load your custom palette next time you restart the application.