WASHINGTON — You may have heard that D.C. United is playing in something called the CONCACAF Champions League. You may not know exactly what that means, or what it is at all. With tournament play resuming Tuesday, we’re here to fix that.

The CONCACAF Champions League is an annual club competition among the professional teams of North America, Central America and the Caribbean. It begins with 24 teams, but exactly how those teams are chosen and how they advance is a bit more complicated. Follow the slides to see how D.C. United has made it this far, and what they have to do to win and move on to the FIFA Club World Cup.