When more than two candidates run for the same office, it often happens that no candidate receives a majority of the votes. When that happens with RCV, the candidate in last place is eliminated and votes for the last place candidate automatically roll over to those voters’ second choice. All votes are then tallied again. If still no candidate has a majority of the votes, the votes of the candidate in last place are again automatically rolled over to those voters’ next choice, and so on. This process continues until one candidate receives at least 50% of the vote and is declared the winner.
In a race among three or more candidates, if one candidate receives a majority of the votes cast in the first round, that person wins the election. There would be no need to go through additional rounds.
Click on the video below to see an easy explanation.