Prior to the arrival of Europeans in North America, Aboriginal peoples were organized as sovereign nations. They had their own cultures, economies, governments, and laws. They were generally in exclusive occupation of defined territories, over which they exercised governmental authority (jurisdiction). They also owned the lands and resources within their territories, and so had property rights, subject to responsibilities placed on them by the Creator to care for the land and share it with the plants and animals who also lived there.
The inherent right of self-government that Aboriginal peoples have today in Canadian law comes from the sovereignty they exercised prior to contact with Europeans. It is inherent because it existed before European colonization and the imposition of Euro-Canadian law. Aboriginal rights to lands and natural resources are also inherent because they pre-date European colonization. They are communal rights that come from occupation and use of the land by Aboriginal peoples as sovereign nations.