How To Verify Lineage And Tribal Eligibility

Hi everyone,
About ten years ago I learned from an aunt of mine that my great grandmother was a full blooded Ocmulgee Creek from Georgia. That means she, and my grandmother, were (are) half creek.... which makes me 1/8th.
I went to the Dawes roll listing and found my great grandmothers name, but navigating such a cumbersome website is frustrating. Does anyone have any tips on how to verify one's native American lineage or experience doing this? It's fairly important to me... as it probably is to all of us!
Thanks guys
cvann5 cvann5
51-55, M
Jan 10, 2013