This is a raglan style sweater, meaning it's worked from the neckline down. It utilizes triple/treble crochet on a larger hook, so it works up fairly quickly. It's supposed to have a looser fit, which makes it perfect for lounging around!
The color chart for the heart is worked upside down. It's a pretty simple chart consisting of only 2 colors. The sleeves are crocheted directly on the body piece, so there is absolutely no sewing necessary!