Comment 5 for bug 1511703

1. Yes, if /lib/systemd/system-sleep/ doesn't exist, create it with mkdir.
2. Yes.
3. No, unless for some reason you want to limit the script to suspend only, or something. Here's my script:

#!/bin/sh

case $1/$2 in
  pre/*)
    ;;
  post/*)
    hdparm -B 254 -S 120 /dev/sdb
    ;;
esac

4. Yes, with chmod u+x <filename>.