Hi John, welcome to the club of us confused DNA researchers! I only began to have success when I began putting *every* DNA match into my tree, and using all the tools that Ancestry offers - good notes on the DNA match page, assigning each known person a color with the dot system (and all their matches in common with me), assigning the correct relationship, and using the little tool to connect the match to their place on my tree, creating a DNA fact for each with the size of the match, and if I see them on other sites, and finally, using My Tree Tags all the way up my tree to our most recent common ancestor(s). I've been working on this for a few years, and am now using Thrulines (at Ancestry) and the tools at Gedmatch, MyHeritage and Family Tree DNA - and put all those people in my Ancestry tree. Wikitree keeps giving me great DNA hints too!
Don't give up -- DNA is a source like any other that we use in genealogy. The tiniest bit of information can crack things open when you look at it again. The adventure never ends.
All the best,
Valorie