A Point Spread, or Handicap, applies a points adjustment to the match result. The favourite must win by more than the spread for the bet to win, while the underdog can lose by less than the spread (or win outright) and still cover.
For example: the Dolphins are -10.5 against the Sea Eagles, so the Dolphins need to win by 11 points or more to cover the spread. If they win by 10 points or fewer, or lose the match outright, the Sea Eagles cover instead.