Use the OR boolean operator, in upper case, to include alternate spellings, synonyms. or related terms; enclose the terms within parentheses (); this technique CANNOT be used in the first box, but CAN be used in the second or subsequent boxes.
The asterisk (*) is the truncation symbol. (e.g., argentin* matches argentina, argentinian, argentine, etc.)
You can use the drop down menus to change the index labels. In this example in the second box, "title" was changed to "keyword".
You can add additional rows to your search.