The filtering fields will give successively narrower results, the more things you have filtered for.
If you don't get many hits, try broadening your search criteria a bit.
To search for an exact phrase, put it in quotes.
Topics are generally reserved for "deep dives". Shorter posts don't use topics. Use tags or search for words instead.
If you have searched for a word/phrase, results will be sorted by relevance. Otherwise, posts are sorted by date (newest first).