Lovely blanket. All squares are crocheted the same, but in different colors in a given pattern. Arrangement is shown in the pictures.
All rounds are shown in the phototutorial. (If you know how to you could print this as a PDF for your reference.) The site’s download for the pattern contains a diagram but not the phototutorial.
From the basics in the pattern you have to decide the size and do the math yourself for number of skeins of different colors for the type of yarn you have chosen.