How to claim flight
Before submitting flight you have to be registered to the contest. This can be done by the "Registration" menu. Each pilot can be registered only once!
After sucessful registration you have to be logged in the contest. This can be done be the entry form (user name/password) in the top right part of XContest:
After a successful login the right menu will display the "My Contest" menu containing the "Claim flight" for registered and logged pilots. All you need now is valid IGC file.