When there are different instructions for two parts of a project like your sleeve, I find it's easier to write out the directions for each row and then check them off as I go.
Dec 1sts on each side (right and left) on rows1,3,5,7,9,11,13,15,17,19,21
Dec 2 sts on the left side rows 24 and 26; dec 1st on right side rows 23,25
Dec 1sts on each side row 27
Dec 1sts on right side row 29.
If you want to see bind off, check the Free Videos tab at the top of the page, Cast off. It just like binding off at the end of project but you only lift 2sts over the needle and off. As Sue said, you can't really bind off at the end of the row (23 and 25) so bind off at the beginning of rows 24 and 26.
Raglan sleeves usually have a longer, more gradual decrease than set in sleeves and it's usually symmetrical. In your case, the decrease is asymmetric.