“AND” is the simplest to use that returns results having both the keywords. For instance if you type in “consultant AND analyst” it would give results that contain both the words “consultant” and “analyst”.
Next in line is “OR” that gives a more expanded search result, including one or more of the stated words. For instance the search phrase “hairdresser OR stylist OR beautician” will return results having any of the words.
“NOT” helps in excluding certain closely related words that otherwise will keep popping up in search results. For instance “writer NOT underwriter” will help give results, excluding the word “underwriter”.
For a particular phrase in a certain order “Quotation Marks” come in handy. The words senior manager may not return results for the phrase senior manager but those having the words separately. The quotation mark becomes useful here. “senior manager” typed that way with the quotation marks gives results containing only the exact phrase.
For more complex Boolean searches these basics are used in various combinations besides brackets and truncations symbols like “ , *.