From the designer’s website:

Two strands of sportweight yarn in two different colors are held together to create a softly shaded watercolor look. The number of color repeats per diamond varies with size. The camisole uses a fun-to-knit mitered diamond. Decreases in the center of every other row form the diamond. A patchwork look without sewing - diamonds are knitted together as you go! Reversible front to back, so you get 2 camisoles in 1.

Instructions included for 16 sizes, from 32” to 62” bust.
Yarn used is a double-stranded sport weight (usually knits at 6 sts/in using a single strand). You will need sport weight cotton in 6 colors.

Garter square size is more important than stitch gauge
Needles: US 6 to 8