This part of your Settings is fairly straightforward. Still you may need to update whether you prefer a 12-hour or 24-hour way of reading the clock.
In a 12-hour time format, 5:00 pm or 6:00 is the time most people head out of the office. In 24-hour time format, or military time, that is 17:00 or 18:00.
It’s totally your preference. The time zone however is not.
Your time zone should sync – but if you need to adjust when traveling, this is the spot to do so.