Here's how:
Adjective: When used to describe something as being equipped with or operated by people, it functions as an adjective.
* Example: "They landed on the moon in a manned spacecraft."
Verb: When used as the past participle of the verb "to man," it refers to the action of supplying with personnel.
* Example: "The factory was manned by a team of skilled workers."
The specific part of speech depends on its context within a sentence.