Ringtone I downloaded and saved in Files (not music) on my iphone 5SE please

If you're talking about custom ringtones, here's what you can do:

You'll need a computer to store your custom ringtones in. Import the files to iTunes Ringtones. Connect your iPhone to your computer and let the ringtones be synced to your iPhone. Once syncing has been completed, go to Settings > Sounds > Ringtone and your custom ringtones should appear on top of the list of pre-installed ringtones on your iPhone.

You don’t.

Use tones and ringtones with your iPhone, iPad, or iPod touch - Apple Support