Complex sentence: Any persons would be received by the British, either at a military outpost or aboard British ships and those seeking sanctuary could either enter His Majesty's Forces, or go "as free settlers to the British possessions in North America or the West Indies".
Split into simpler sentences: Any persons would be received by the British, either at a military outpost or aboard British ships. Those seeking sanctuary could either enter His Majesty's Forces, or go "as free settlers to the British possessions in North America or the West Indies".