Alternative Vote Plus is a way of choosing leaders in a special way. You get to pick and choose the leaders you like through different rounds of voting!
First, everyone gets to vote for their favorite candidate. Then, the leaders with the least number of votes get removed.
Once the ones with the least votes are gone, the people who voted for them get to choose someone else to vote for from the remaining leaders.
The process repeats, with the lowest-scoring leader getting kicked out and the remaining voters getting to choose someone else, until there's a final winner.
Alternative Vote Plus makes sure that the winner has more votes, even if not everyone voted for them originally. It's a way of making sure that the most people's opinions are taken into account when picking a leader.