Many DNA matches took their test because they received it as a gift or had a passing interest in their ethnicity. If you are lucky their tree has at least a few names in it. Remember that what’s in many of those short trees are based upon what the person knew from personal memory or perhaps what close relatives told them.
As a result, maiden names may not be correct and may be last names of step-fathers or previous husbands. First names may be incorrect as well. If you are lucky these testers communicate with you and some information can be corrected and the known lineage extended.
If they don’t, you are left with what’s in their tree. Be flexible in using the information they have in their tree–but use it as a starting point.