Anyone play netball ?

There is a netball competition at the National at Arley Hall, ok there is one every year, but this year my OH and I are running it for the first time and I haven't played netball since I was at school ( a very long time ago) and obviously he has never played (he was a volleyball player) so is there anyone out there who does play netball, preferably at a National, and who knows what format this competition usually takes ? Entries are starting to come in, I'm pleased to say, so it looks like there will be a competition this year, but it would be helpful to know how long they are used to playing for. Every page I google says different -anything from four quarters of 6 minutes to two halves or three thirds of more !! very confusing ! Any help gratefully received 

Alison