Anti-plurality voting is a way of choosing a winner when there are several people who want to win. It's like choosing who gets to play with the toy truck when you have several friends who want to play with it. Anti-plurality voting means that you get to pick who you don't want to play with the toy truck, instead of who you do want to play with it.
Here's an example: imagine there are three friends who want to play with the toy truck. Their names are Timmy, Sally, and Billy. You get to choose who you don't want to play with the truck. Let's say you don't want to play with Timmy. So you say, "I don't want to play with Timmy." Then everyone else gets to say who they don't want to play with, too.
Let's say that Sally, the girl who always takes your crayons without asking, says she doesn't want to play with Billy. And then Billy, who always interrupts your stories, says he doesn't want to play with Sally. In the end, Timmy is the only one who nobody wants to play with.
That means Timmy is the loser and Sally and Billy get to play with the toy truck. They can take turns or they might work together to make a game to play with the truck. Even though you didn't get to choose who you wanted to play with, you helped decide who wouldn't get to play with the truck. That's what anti-plurality voting is.