Bascially, anybody who is registered on the council property list can bid on a property but a person/family with 'priority' will be offered it first.
Most adverts will state "Priority or estimated waited time 5 to 10 years" This means if somebody with a 'priority' status has bidded on that particular property then this will be given to them in the first instance and if a priority person hasn't shown interest in that property then it will given to the person/family who have been on the council list for the longest amount years. However, there is a 'first come, first served' section of properties but these are mainly aimed at over 55's.
I'm a 23 year old single woman and can't afford private rented accomodation. I've been on the register since I was 16 and have been bidding on all 1 & 2 bed flats in Sheffield every single week since February 2011 and haven't been offered anything! I was assessed last year to find out if I could become a 'priority' and was told you are only granted 'priority' if you are a single woman and pregnant, homeless, an immigrant or an ex-offender. I'm actually thinking to give up now as it doesn't look like you get a chance if you're not priority!