First season has a fairly steep learning curve but not like GD (from what I remember, but then again I'm dumb when it comes to football play books). The first preseason is especially overwhelming. After you've got your team on the right track you can spend less than 10 minutes a day.
Stadium makes no difference. Everyone has equal payroll. Main competitive advantage to be gained is in how much time you are willing to put in learning the nuances (asking for help on forums or digging through old posts and dev chats).
Most important thing I can recommend for a first time player is do your homework to find the right league. There a few leagues out there that are run really well, quite a few that are okay, and a number that are always struggling to stay filled. A good commish sets the tone for the league.