How to get to Brother Island
In order to reach Brother Island you'll first need to travel to Tempest Temple. For more information on How to Get to Tempest Temple follow the link provided to be taken to that guide. Once in Tempest Temple you'll have to wait for the boat in the eastern portion of the zone - that's right... Actually wait for a boat!
When the boat arrives, hop on it to set sail for Brother Island! That's all there is to it. Brother Island is the only T2 TDS zone that does not require any flags to zone into.