Use the AND option to add another field to your search - this will narrow your search to only items that have both fields. Use the OR option to broaden your search to include more items.
Use as many or as few of the Search Filters as needed.
Under the "contains" drop-down menu, there are several useful functions in the Advanced Search mode.
For example, there is a new YA novel about the Gulag prison camps called Between Shades of Grey, by Ruta Sepetys. If I couldn't remember the whole title or author's name, but didn't want 50 Shades of Grey to come up in my search results, I could search something like this:
This search function is useful for finding items from a specific time period. Use before to find items published before a specific year (useful for tracing the history of a subject), after to find items published after a specific year (useful for finding current research on a subject), between to find items published during a range of years, and is to find only items published in that year.