Court proceedings time scale

Possession - Section 8 and Section 21

I have now got a court date having served a section 8, however I am unsure of the next steps as timescale is concerned, I understand that the judge will give a possesion date , and only if the tennants do not go on that date , the baliffs will/can be ordered to reposses my property for me, can anybody tell me how long this all takes to reach its conclusion, as I had thought that once the possesion date was given by the judge the baliffs automatically went in on that date to make sure the tennants had gone??? I need to know how long it takes from possesion date to actually being able to get my property back , do I need to go back to court and wait even longer before the baliffs can go in???? thnks