Use this world: MCPE_V4_SH0WT1M3_ACHIEVEMENT_WERELD.mcworld
You can import the world onto an ios device by following this video:
Credit to OMGcraft - Minecraft Tips & Tutorials!
You simply need to pick up all items from the chest on the left. It is easiest to simply destroy the chests, thereby picking up all colors of wool and then the achievement should be earned.