Questions for a new nex owner-please help

I am hoping to get help with this.  I have a nex 5n.  I have a 55-200, sigma 30.  I am considering the 19 also.  Not sure if I need it.  In your experience do I need a better flash?  Also where would be a good place to go to get basic tutoring on using the old lenses and adapters.  It is quite overwhelming and I don't know where to start.  Thanks so much!!!