After you killed all zombies on the floor, you can move on and open the trapdoors in the ceiling of the survival arena to start the next wave.
How to install:
- Download and unzip archive
- Then go to the any File manager
- And copy the map in to the "/storage/emulated/0/games/com.mojang/minecraftWorlds" folder.
- Once you've done, you can open Minecraft PE
- Map will be among your worlds