Race one (feature race) is about an hour and awards the same points as F1. Grid decided by qualifying, which isn’t knockout or anything fancy like that, just an hour (I think) session like F1 had a decade ago.
Race two (sprint race) has a partially reversed grid. Last year it was top 8, but with the points now mirroring F1 it may be top 10 (so tenth place finisher starts on pole, ninth starts second etc). Not sure on that though. Points in this are only awarded down to eighth and are less than in the feature. Not sure what for 2012 as it’s changed. There are also bonus points for pole and fastest lap in each race.