@laurenjw11 you need to be on the website, not the app. Just click "add a variation" on the top right and change the colours however you like. Then you can submit the variation.
@Aicha-R the pattern doesn’t need to be longer. It’s essentially a repeating pattern, The only thing that changes is the colors. If you look to the very right, the two F colors at the top are now replaced by two D colors on the bottom and so on through the whole pattern. What you could do if the changing colors throws you off, take some grid paper and draw out the repeating pattern but with the colors as they continue to flow throughout the pattern.