The map is originally split into 2 sides, Angels or Demons these islands are then split into 16 lands.
When you first login you are asked to pick your side, and this will open up the corresponding island. The map is where you can stake your heroes to participate in an early version of the reward/battle system in exchange for SOULS. Each area on the map has a corresponding xp cost to assign heroes there and can only have up to 3 heroes assigned to it each day.
Rewards are then assigned based on your collective hero power in each area compared to other players in that area, rewards SOULS once a day.