The sweater is worked top-down. Stitches are picked up from the narrow strips of rib for the saddle shoulders. First work the back, then work the front downward to the base of the armholes back and forth.
Then joining front and back, the rest of the body is worked in the round with side decreases downward for a slightly tapered fit. When working the sleeves, stitches are picked up along the armholes. In addition, the sleeve caps are formed working short rows, and the sleeves are worked in the round from the armholes to the cuffs with decreases along the way.
Finally, the turtleneck is worked back and forth from picked-up stitches along the neck opening, adding more buttonholes at the front edge along the way.