Questions about the Zoom H2N audio recorder

I acquired a Zoom H2N recorder a while back. I recorded my daughter playing piano at home and at her piano teacher's home. I downloaded the files and the sound was very low. I did use Audacity to boost the volume but I want to get the best recording possible with the Zoom without having to fix much in the Audacity software. I noticed that the gain was on zero and believe that was the problem. I should have paid attention to the setting before I recorded....ugh!!! Those little numbers on dials are not as easy to read as they used to be . What would be the best settings for recording with my Zoom? I would like to record my daughter's piano playing especially at recitals. I also intend to use it in conjunction with my video camera to do vids of me playing my dulcimer.

Any suggestions you have would be most appreciated. Thank you!!!