Complex sentence: The low points scoring system is used: a boat that finishes 1st earns 1 point, a boat that finishes 2nd earns 2 points, and so on--with the winning team decided by adding together the points of all the boats in each team.
Split into simpler sentences: The low points scoring system is used: a boat that finishes 1st earns 1 point, a boat that finishes 2nd earns 2 points, and so on. In team racing the winning team is decided by adding together the places of all the boats in each team.