This scarf uses the tapestry technique.
That is, you crochet (in this case) dc’s in one color and you carry the other color along with your work.
You create an image in your work through color changes.
So for each row you use 2 colors.

The pattern describes both shawls, one with 2x Scheepjes Whirls and one with Scheepjes Organicon

The pattern also has a clear chart.