So I finished editing my video and downloading it. Now that I replay it, I can't hear the music I added, which is on audio track 2. I could see video track 1 for my subtitles. How can I fix this? I used the YouTube preset, but instead of Quicktime, I changed it to mp4. Edit: Nevermind I figured it out, by changing audio from all timeline tracks to Main 1. But I still don't know why all timeline tracks limits to one track.