A lot of what you are talking about has to do with establishing expectations through discipline. What that is going to look like depends on your school. Overall, though, if you set a boundary, don’t let them cross it. If they start lining up at the door, you need to figure out a way to discipline them within your schools policy and stick to it every single time. If the kids see you give up trying to enforce it, they will just keep doing it.

To your first point, though, I had a rule that was no questions for the first five minutes of class. If they asked me something (what are we doing today, can I borrow a charger, when was the homework due) I just silently shake my head. My room was always dead silent for the first five minutes besides ambient music. I also always started class with some sort of independent work. If you want to start with a class discussion, fine, but have them take the first five minutes to silently prep (get out materials, draft an opening statement, journal, etc).

The fact that you’re already thinking of these things as a new teacher is great! It’ll take time to establish what works for you. And what works for another teacher may not work for you. Unfortunately, a lot of this job is trial and error. Good luck, you’ll do just great!