Denver International Airport is one of the largest airports in the United States, a common layover destination, and divided up in a way that is quite different from most airports you might be used.
Even though it is well organized, the Denver Airport can be a confusing airport to navigate, as the concourses are separated from each other by a train (tram) and there is no alternate one to get from one to the other if you find yourself in the wrong wrong.
Also, the train is located on the lowest floor of each concourse, meaning you will need to traverse either the escalators or elevators to access it and then back up again to get to your gate.
Because of all of this, give yourself extra time to navigate!
If you are looking for an interactive map, use the official one here.