Let's say you want to draw a square with your new spot color. You just need to make sure that the only channel that is selected is the one with your spot color, this way whatever painting you do or whatever shapes you make will have the spot color. Note that when you have selected your spot channel, your foreground and background colors in the Tools palette will only be black, white or shades of gray. That is because you are working only on 1 color, i.e. your spot colors, where black indicates the maximum intensity of your spot color and white indicates the total absence of it. Gray indicates a tint of your spot color.

