As soon as you start a movie the app will register your progress so that in case you need to interrupt your session you can continue later.
If you need to stop watching the movie will show up in a new section called Continue watching which you can find on the start page. You can access this collection on all devices (web, Android and Apple) which means that e.g. you can start a movie on your mobile while you commute and continue at home on your big screen.