This is a really simple one for all you researchers. You may know about it. It is easily found by just searching Google for your family DNA project. So I type Butler family tree DNA project and the site will come up in the results. You can also use this link, with your family name of course.
https://www.familytreedna.com/groups/XXXdna/about - xxx equals your name.
The wealth of information here is amazing. The most important parts are the DNA results and the Surnames sections. You should try to find people in the Surnames or Results section who claim common ancestory. They are grouped by likelihood of relationship, expressed as a Haplotype, and if you are in the same group or a simliar group you are closely related. Same Haplotype means your DNA is nearly identical and you have a common ancestor within a couple of generations. I have seen some inconsistency with groupings and Haplotypes, but this is a good place to start. The closer your DNA matches with someone else means the higher likelyhood you are related.
Surnames section will have the purported trees of the donors. Another great place to get information, some of which may not be correct. Much like using a commercial tree builder.
I hope this is valuable to all of you who don’t know about this! It has helped me so much.