Here are the directions (got this from last April's Teen Vogue - taken me time yet?):
1. Remove buttons from a long sleeved cardigan and line with grosgrain ribbon.
2. Sew vintage buttons on using needle and thread
3. Cut the sleeves at the elbow and fold them 2x; sew cuff in place
4. Stitch one big button to the outermost point of each sleeve cuff