- Should I always start project by using project settings or the video's settings?
What are those projectsettings and what are the settings of your sourcefiles and your intended export goal.
What is the best format to go with?
If your exportgoal is Youtube look for the settings in the YT needed specs you have to use for your goal to show there.
Which template to use? and how to customize it to give best results?
That also depends on your exportgoal and -settings, look above.