That means that you want to make sure that colors 1 and 3 are light, and colors 2 and 4 are dark, and the accent colors reflect the colors you want to assign to objects.
When you’re creating a new color palette, you want to make sure that you stick to the color types indicated in the palette, because this is how PowerPoint will assign colors to your presentation. The first set of four colors defines the colors of the slide backgrounds and of the text, and the second set (the six accent colors) defines the colors for shapes, tables, charts, SmartArt, etc.
