How to use ashnar
Ashnar means "someone/something does/did (an action)," specifically, someone or something that is either unknown to the speaker or that the speaker wants to be particularly vague about. You can also use ashnar when you want to show that the object of an action is more important than the one performing the action. (It can help to think of ashnar as another type of pronoun; it's listed as a phrase in in the MandoCreator dictionary because it may only be used as the subject of a sentence.)
Ashnar can be followed by an action noun or a conjugated verb. In modern English, this is similar (but not exactly like) using a noun as a verb without changing its stem.
Differences among ashnar, ash'ad, and adat
Use ashnar when the actor is unknown; you want to be vague about who or what performed the action; or you want to emphasize the action rather than the actor. Ashnar cannot be used as an object of an action.
Use ash'ad (pl. ash'ade) when you are talking about an actor who is not in your group but who you might know or could figure out who it is. Ash'ad can be used as the object of an action.
Use adat (pl. adate) when it applies to anyone in general. Adat can be used as the object of an action.
Examples for ashnar
Tense in all cases in determined by context.
With a verb:
Ashnar sirbu. Someone is speaking. Someone has spoken.
Ashnar sirbu ibic miite. Someone is speaking these works. These words are being spoken by someone. Someone has spoken these words. These words were spoken by someone.
With a noun:
Ashnar beten. Someone has performed/completed/accomplished/done a sigh.