Hello!

Season Event Interface comes available at Level 30. Season Event starts every after a Season ended, like for example this season, it started in September and it will end in November. Though one case might apply to prevent this interface from being available and that is if your server is newly opened and the opening date of your server was after the season started. If that's the case then the most probable thing to do is just to have patience and wait until the next season comes. Hope you understand it and thank you.