The Relation field links lines of Search criteria together. To get accurate search results, it's important to choose the correct Relations.
Limits the universe. You'll use AND most of the time. It helps whittle the universe down to just those funds you want to see. For example, use AND to see all funds that are Small Company AND 5 Stars AND Distinct Portfolio. A fund would have to meet all of these criteria.
Expands the universe. Use OR to widen your search criteria to include more than one of the same thing, like more than one Morningstar Category. Also use OR to see more than one group of funds in your search results. For example, to see funds that include all Vanguard Funds as well as all funds available through Charles Schwab One Source, use OR.