The set of rules were quite straightforward.
First, there was a limit on how much land each person could take. If this limit wasn't imposed, some groups would literally try to take the entire south of the island to themselves.
Second, killing was expressly prohibited in Freedom Island. If you killed someone, you would be killed back unless you were confident you could run away from this place. However, it would be pointless to run since everyone's idea was to stay.
Third, if you wanted the same land as someone else, both would have to decide who would take it based on luck. Strength would not be the main factor. The idea was to create a city, and battles would definitely delay everything.
There were more rules, but these three were the main ones. However, most of them stopped reading here.