Savile Row Garments making

Hi, I have arrived at episode 30.1 turning up the back hem and tacking the vents, it seems that the coat is now sewn together at the vents where it wasn't before when we left off at episode 30. Also the back vents seem to be turned in and the lining basted. Apologies as this is my very first time making a coat and it is a bit confusing. I am wondering if someone might help bridge the steps between video 30 and 30.1 for me, or perhaps I am misunderstanding