The first thing you must do is register with the council. This will automatically register with the Housing Associations in your area.
If you have a family you will be given bed and breakfast at a push. Unfortunately due to general incompetence in some town halls and DWP offices, you could find yourself on the streets.
Contact the housing unit immediately, and ask for a list of accredited landlords. These are private landlords whose properties have been vetted by the council as safe.I.E. gas safety checks etc. They will also accept housing benefit.
Some councils will pay the deposit for you, if not, you can ask for a loan from the DWP to pay it. You do not need to be claiming benefits to qualify for a Crisis Loan.
The main thing to do, if you haven't done it already, is to get your name on the housing list.
Email me if you have problems, some areas have empty properties now waiting for tenants and others it will take years.