Seven people are running, there are three open seats, you get to rank three, and your rankings matter. I find the counting process with ranked-choice ballots fairly intuitive for single-winner elections, but much more confusing for multi-winner elections. However, this video does a good job of explaining it:

The key things you need to know: you should definitely rank people in your order of preference, and don’t worry about “wasting” that top slot on a candidate you think will be broadly popular. Voting for a second and third candidate will not hurt your top candidate’s chances.

On the ballot:

Katherine Kelly
Charles Rucker
Meg Forney
Londel French
Tom Olsen
Mary McKelvey
Alicia D. Smith

You can rank your top three.