Help with a jacket

[leslie979]

Hi all. TIA for any help provided. Im making this. http://www.garnstudio.com/lang/en/vi...d_id=8&lang=us
Ive got the back done now Im starting on the lt front piece.
For the lt front piece it says decrease at side as described for back piece 41 sts. (started out with 45). So on the back you decreased 1 st each side 4 times for a total of 8 sts decreased. Obviously Im only going to decrease on one side for the lt front but it doesnt say what side. Also for the buttonholes it says bind off 5th front band st and cast on 1 new st on return row. Where am I casting on this stitch? By the bound off stitch?