ERJ 175 FMS Radio Question

[Sfgiants13]

This may be a dumb question but I couldn't find the info in the manual.  When programming the FMS, the radio screen is set to "FMS auto" for both NAV1 and NAV2 unless I manually put in a frequency.  

 

1)  What specifically does FMS auto mean?  Even if I plug in a frequency manually, when I use VNAV/LNAV it still runs off of the FMS.  Does it just mean it's going to show and autotune the closest VOR freq on my route?

2)  Once I do put in a frequency manually, how do I get that NAV radio to go back to FMS auto (even though I'm not sure what exactly it means)?

3)  How do I pull up the NAV2 radio on the PFD?  

 

Thanks