For affordable housing : they will be able to tell you what developments are coming up and which ones you may be suitable for price-wise. For affordable housing they don't do anything about mortgages so you have to do that yourself. If you don't have approval in principal yet they will tell you to go to the banks and see what you can get. Only then will you be put forward for a place. They will go through the application form you filled out to make sure its filled out correctly with any bits and pieces needed and will tell you about the process. Its all very casual.
If you are going for something other than the 'affordable' options, I don't know.