If you are just starting to race enduros, the timekeeping is probably as baffling as anything you've ever encountered. What I hope to do here is to make it a little less mysterious.
Key time is simply the master clock used to set all the other clocks in an enduro.
In other words, if you're one minute early, you get two points. Being early, a.k.a. If you are late, you obtain one point per minute late. Now, to know where the checks are, you need to know where they can't be. Checks can't be in the 3 miles after a check, or the 2 miles before a known check, like a gas stop, or known control or finish.