I don’t remmener the exact steps, but it was fairly easy. You just need a mac (which you can borrow) and an audio editor. But that’s been a few years as I’ve been using the same one for a while now.
Yeah, so only-iPhone users are out of luck since the majority of people don't have a Mac. Last time I used Android you needed the file and the phone itself, you select the audio file and you're done.
