As the others said, you just ignore the blank space. It's just there because the hat isn't a flat rectangular shape, but the paper the chart is on is a flat rectangular shape. Kind of the way a flat map of the globe sometimes has blank spaces at the top and bottom. It can be a bit challenging to train your eye to skip the white space, but once you get used to it, it's not hard.
Also, you can always write out the instructions from the chart, and then knit from the written instructions.