Can you please check the sentence? Because "санаа авангаа" doesn't make sense in this sentence.
The basic form of авангаа is aвах. Usually -нгаа (-нгээ, -нгоо, -нгөө) mean that some actions are happening at the same time. In Japanese is would be ~ながら
Утсаар ярингаа цонхоор харах.
Алхангаа хөгжим сонсох.