Have you gotten an ID from Gedmatch yet? If so you'll want to post your ID on you profile in WikiTree and it will then propigage the ID to your relatives where you may have a match. But you can go to Gedmatch and find all the ID which have one or more matches to your test ID and then see if you have any matches with Wikitree members. You'll probably have hundreds of matches and can work through them to try to figure out which of your ancestors the matches come from. You get the e-mail address of the matches and once you check to see that it's a real match, you can e-mail the person to see how they may be related.