Kill 100 monsters in each arena to progress. First you select the arena then you select your class. Each class has it’s own unique skills and strengths. If you die before you are able to kill 100 monsters in the arena, you will have to restart that arena. There are 10 arenas, 10 classes, and 4 difficulties which makes for over 100 different ways to play. The in-game tutorial should give you all the info you need.
Set the following settings in the server.properties file:
Resource Pack: Inside the download