Find how to make the fabric buttons here.
Find the cardigan pattern here.
Find the scallop pattern (for the edging) here.
I was only off by one stitch by the time I switched colours. I figured out that the arm holes are to be stitched in the 20th stitch, not the 19th. But, at the end of the first jade row, I was down two stitches (after compensating for the original "missing" stitch).
Note that for the scalloped edge on the bottom of the cardigan I made sure the first scallop was started after I had made the front edging (for the buttons and button-holes). The scallops were made in the "spaces" between the puffy-looking rows. (For the green cardigan, I made the scallops before the front edging, and scalloped into the ends of the puffy rows.) I recommend doing the scallops as your last row so that the front edging is tied in a little nicer. I also only double crocheted 5 (instead of 7) stitches for each scallop.
The buttons really hurt the ball of my thumb to make. I think this package had smaller buttons than my previous batches. They're labeled as the same size on the packaging, but I am keeping them separate from my other ones, just in case the pieces don't match up size-wise.
Neckline: on row of single crochet, I decreased (front loops only) after every 4 stitches. I added another single crochet row with the jade to add some trim, also decreasing after every 4 stitches.
Sleeves: I added a row of single crochets for a teal trim.