I have to say I am rather confused too.
From my understanding the Grammar Schools remain on the whole unaffected. All other secondary/comprehensive schools will have to do an 11plus style examination [apparently in non-verbal reasoning].
From these examinations the children will be grouped into 8 sets of ability.
Then every (non independent) school will be forced take a quota from each ability group, so each school becomes a mixed ability school.
I may be totally wrong but there is plenty of details in the news section of this webiste going back up to four weeks, try: