Need to find my ancesters in Canada How do I find documents?

Looking for my native american great great grandmother All I know is that she full blooded Chippewa or Ojibwa She was born in Canada Married William H Lemon On April 28,1874 He was from Wisconsin But my Great Great Grandmother names is MArgaret Henderson she was born in Ontario CAnada and she born May 10,1850 Need to find her birth certificate and other documents and need to see if she had other siblings and relatives