Open Settings. 2. Tap the Sounds section. If you don't see a section with Sound in the title, type "Ringtone" into the search bar at the top of your Settings app. 3. Tap Phone ringtone. 4. If you get an "Open with" or "Complete action using" prompt, select the system's Sound Picker app instead of a file manager. 5. Tap the custom ringtone you added to the ringtones folder. 6. Tap Save or OK. If you do not see these options on your device, simply tap the back button to exit the ringtone picker. 7. And enjoy.