Once your Lighthouse is restored, you can join a community or create your own one. 
You can create your own community for 20000 coins.

Being a community member gives you an opportunity to travel to Community Island, 
explore it, collect unique resources and receive unique gifts!

Together with other players  you will be able to accumulate resources into a common storehouse.

Only the leader of the community can rebuild any buildings in the community,
the others can help him by contributing resources.