Nancy Marchant’s website gives excellent instruction in stockinette brioche, both one and two color versions.

Great color photos of top and inside view. Also a diagram noting all measurements (11.5” diam when flattened, but you can knit it smaller if you prefer that).

Instructions are row-by-row, then move to a table to indicate changes to MC or CC at which stitch in each round.

9 different beret patterns using two-color stockinette brioche are provided (free), using a variety of suggested yarns and color combinations. Each has a the solid main color defining a repeating pattern. his one is named “ZigZag”.

Other Berets in the series are:
Whirlybird
Lemon Slice
Rooftop
Pinwheel
Windmill
Ying Yang
Tree
Bottoms Up

Well worth reading, an excellent resource.

Direct PDF download