Complex sentence: The Siksika Nation is in the process of developing a framework for self-government, which will define, and control the Nation's own destiny, and remove it from jurisdiction of The Indian Act, which was legislated into force by the Canadian Government in 1876.
Split into simpler sentences: The Siksika Nation is in the process of developing a system of self-government. The new system will supersede The Indian Act, which was legislated into force by the Canadian Government in 1876.