Blightfall

Alright. Ive searched all through everywhere. Ive created new worlds on single player, ive downloaded the map from their website and tried to upload it. No matter where i get the world from, or where i look i cant get it to work. Blightfall functions under a custom map. If you genorate a world using aternos, you just get a normal world, and if you generate a new world in single player, zip it, and then attempt to upload it. The file is too big. How do I get it to work....