All athletes that participate in World Ranking Events in any of the orienteering disciplines need to create themselves a user account in IOF Eventor before taking part in the event.
This is what to do: Go to eventor.orienteering.org, and click on Create user account. Please choose the first option: “I am an athlete participating in events”. After filling in your information, if you have earlier participated in WREs, IOF Eventor will ask you: “Are you this and this person”? You will then have to choose yourself on the list, and your account will be merged with your results.
User guides for IOF Eventor can be found here: http://eventor.orienteering.org/Home/HelpAndSupport
News article about this: http://orienteering.org/all-athletes-need-an-iof-eventor-user-account/