What is guerilla warfare and how was it used by the patriots?

Guerrilla warfare is a form of irregular warfare in which small groups of combatants, such as paramilitary personnel, armed civilians, or irregulars, use military tactics including ambushes, sabotage, raids, petty warfare, hit-and-run tactics, and mobility, to fight a larger and less-mobile traditional military.

And Guerrilla tactics were first used in the US at the Battles of Lexington and Concord by the Patriots at April 19, 1775. George Washington sometimes used some sort of unconventional methods to fight the British. ... Nathanael Greene used a guerrilla strategy very effectively against Lord Cornwallis.