If it doesn't work out, don't lose hope, all you gotta do is go into your "files app" search for the notification or ringtone you downloaded, edit it, and move it to "notification" or "ringtone" folder, there you'll switch to settings and "sounds and vibration" and chose what you want.
"Darling ohayo" I kept this as my alarm...and when the nxt day i woke up....I WAS IN TEARS WITH THE ALARM😢 Only Darling in the franxx fans will understand ❤😢