The columns after the first one are for each individual contour level. In each level column, change the Color setting from black to a different color making sure to use a different color for each level. When a level color is changed in the property sheet, that level is updated in the iContour display.
The resulting display contains a different color contour for each level.
After changing the colors of each level, click OK in the Contour Levels property sheet. The Contour Labels property sheet closes.