Star stitch - https://www.crochet365knittoo.com/crochet-star-stitch/

The jacket is done in one piece, without side seams. Shoulders and top of/the length of the sleeves are closed with single crochet.
1 star = 2 stitches
- start with 72 stars plus 1 edge stitch = 145 stitches
When comfortable underarm height is reached, divide into 38 stars for back and for each front 17 stars. (Smaller fronts create room for button panel)
sleeves - add 18 stars to fronts/ chain 37 stitches, then 1 row single crochet, then start star pattern.
keep going until sleeve front measures ca 7 inches, then minus 5 stars for neckline.
armhole height = 10 inches
back of sleeves - hook into the combo of the chain stitches plus single crochet, which were used to start the front of the sleeves, 18 stars.
shoulder and top of sleeves are closed with single crochet, crochet on the inside, so seam lays flat.
finish length of sleeves by picking up stitches in single crochet, decreasing from ca 50 stitches at the raw edge to 30 stitches. Then continue straight in contrast color.
Single crochet all around in contrast color and add button holes.