You have to click on ”record” before exporting, and make sure that the phone doesn’t change to lock screen. You don’t need to click on ”stop” if it’s not necessary, the recording will stop automatically when the video or audio is finished playing. Add an acapella audio file, an optional instrumental audio file and an optional video file. You can choose between heavy/natural/harmony autotune. You can choose to export it as mp3 or wav or mp4 before clicking on export.