Will teams be demoted/relegated out of the league as with 'normal' divisions? Or will they just be at the bottom of the league and hope to make their way back up?
No, the founding members of this Super League will remain in it for ever, no relegation for them effectively they could end up at the bottom every time but are still permanent members and will still reap the mega bucks.
It will essentially be the same teams playing each other over and over again, ad nauseum. Normally matches between these 12 are high points as they are not guaranteed and therefore far more interesting.
The Champions League and the UEFA Cup allow the opportunity for teams from different countries to play against the well known 'big' clubs (the ones who are pushing for this Super League) and on occasion beat them, it does happen.
As others have said it will be a very elite closed shop, mega money for the owners of these clubs don't believe their protestations about it trickling money down to all the lower league clubs, it's all about the billionaire owners of these clubs making even more billions.
They want to stay in the Premier League as well, this is after complaining that they are expected to play too much football!, however, the Premier League have intimated that they won't allow them to stay.
It's a mess, battle lines are being drawn but the one and only reason for the club owners who are doing this is money for themselves.