The presidential campaigns have been on full boil in Iowa for months, but the outcome won’t be known until after 7 p.m. Monday night. That’s when our neighbors to the south gather at county fairgrounds, school lunchrooms and community centers to cast the first votes of 2020.

You’ve heard about the outsized importance of the Iowa caucuses. But how do they work? And what do the changes to this year’s process mean?

In a candidate’s corner

Democratic caucusgoers line up at their precinct caucus location or one of the satellite spots, including three international sites. Following a bit of party business, they divide up in groups according to their candidate preferences. There’s a count of the number of people in each group. To remain “viable,” a candidate must meet a support threshold generally set at 15% of those in attendance, though at some spots the bar is higher.

Time to realign

Backers of candidates who fall below 15% have a few options. They can try to convince others to join them, switch candidates, or remain on the sidelines for a second count. This is why respondents’ second choices in pre-caucus polls matter. But people who initially pick a viable candidate cannot switch. And if a group of uncommitted caucusgoers numbers 15% or more, then those in that cluster must stick with that decision.

Candidates who continue to meet the viability threshold after the second round get one or more “state delegate equivalents.” The number of delegates allotted to each candidate is based on a formula.

What about Republicans?

Republican caucuses have a simpler process. Instead of breaking into preference groups, GOP caucusgoers cast ballots for their pick.

Who wins?

The Iowa Democratic Party tallies the delegate counts, though it does not proclaim a winner. News organizations like the Associated Press and CNN plan to announce a winner based on that count. The conclusions might not be so clear.

After intraparty fighting flared between Bernie Sanders’ and Hillary Clinton’s campaigns over the tight results in the 2016 Iowa caucus, the Iowa Democratic Party decided to track and release more than just the delegate count this year. The public also will see tallies of how many people supported each candidate in the first and second rounds, which could differ from the final delegate count.

With a cluster of candidates at the top, the final results could be close — with some candidates emphasizing their vote totals and others emphasizing their delegate counts.

What’s next?

The candidates who emerge on top in Iowa will have momentum going into the upcoming primaries and caucuses in New Hampshire, Nevada and South Carolina. While campaigns will quickly move on, in Iowa the 11,402 delegates from the precinct caucuses will be slowly winnowed down over a series of conventions. Ultimately, just 49 Iowa delegates will head to the Democratic National Convention in July, with 41 pledged to specific candidates based on Monday night’s results.