Hi there fellow virtual pilots. I just got a question about setting an FMC. A tutorial I watched basically told me to go to DEP/ARR and choose the arrival runway/STAR and Transition point, before taking off. I've done that, and I didn't have a hitch with my flight. But then someone just told me that I should not do so until I get instructions by an air traffic controller. However the tutorial I saw was made by a real life 737 pilot and I was wondering which side of the story is the truth. Here is the tutorial I watched. So is this a correct procedure? I mean, you can always change your arrival setting anytime you want right?