The election will be decided using the supplementary vote system – meaning voters can choose to select both a first- and second-choice candidate.
Voters do not have to make a second choice, but, as the official GM Elects website explains, external, if a voter only marks a second choice and does not choose a first choice, their vote will not be counted.
If nobody wins more than 50% of the initial vote, all but the two highest-polling candidates are knocked out of the race.
The second choices of those who voted for the other candidates are then reallocated.
Whichever of the top two candidates ends up with the most votes after this “run-off” round is then declared the winner.