The word "安营扎寨" is formed by combining two parallel verb-object phrases: "安营" (setting up a camp) and "扎寨" (pitching a stockade), where each phrase consists of a verb ("安" meaning to arrange, and "扎" meaning to pitch) followed by its object ("营" meaning camp, and "寨" meaning fortress), together conveying the concrete action of establishing a military encampment.