Simply play normally in a survival world. After a random waiting period, a warning appears in chat. When the warning countdown finishes, the disaster begins automatically.
Keep escape routes, watch the warning messages, and avoid standing directly beside unstable floors or fresh lava. Underground areas can become dangerous quickly during a cave flood.
Disaster effects are intentionally localized around currently online players. Existing lava and water may spread according to normal Minecraft rules. All particles and visuals use vanilla Minecraft effects; no custom textures or models are included.