Total noob here:  I have a new rig just built and i'm trying to decide which OS to boot onto it. 

Given i have no OS right now, does nvOC also serve as the OS?  Or do i have to DL ubunto first?

I'm asking because i went ahead and imaged nvOC anyways, booted it onto the rig, saw a lot of critical core errors, saw the ubunto loading screen and now its asking for m1-desktop-login.