For now I have your basic square rock wall around my village. I have one hero at each corner but it seems as though attackers will have demolished half my village before they go on the defence. What are the rules on placing a hero properly? Do they have to be able to see everything or be within a certain distance from attackers or what?

when the attacks get alittle close to your heros they will attack and sometimes they all attack no mater where they are but its realy were u put them and where the attacks choose to attack