Need Help Finding A Potential Solution to Ancestry

I have been interested in my ancestry all of my life. All of my grandparents have passed on recently (peace and blessings to my ancestors). I always knew that my grandmothers' mom was Creole and my grandfathers' mom was Cherokee, but her mother died at childbirth, and she was an only child. Her uncle adopted her after his sister passed away. Not sure how to get ahold of their birth certificates or death certificates. I would like to know if there is any way I can confirm our heritage and hopefully finally be able to find our tribe.