That’s what we see in germany
how do you combine audio and video in the final movie?
It uses Bach in the beginning of the video, I bet the rights are OK for USA and some other countries but not for Germany.
To answer your question, if you upload to Youtube you can just select an audio track to add, so you have nothing else to do beside uploading the video. But since rights can be unavailable in some countries, as you have seen (or not! ), Sara’s method is better, though it is more work.