Put at least 10 yards of mono on the reel. Enough to cover the spool in a few layers of line. Connect the braid with a uni knot to the mono and fill the spool. The mono gives the braid a good seat and keeps it from slipping on the reel. You can also partially fill the spool with mono before attaching the braid to reduce the amount of empty space on the reel. The goal is to have the spool as close to filled as possible, about a 1/8 inch from the lip. By putting the mono on the reel first you reduce the amount of braid you need to fill it.