The Zedge apps are designed to make it as simple as possible for you to download and set wallpapers, ringtones and notification sounds, but due to the multitude of devices, and OS versions in use by our millions of worldwide users, we regret that we are unable to provide assistance with helping you configure your specific device.
We recommend the following external resources:
Change Ringtone and Notification Volume
Assign Custom Ringtone to Contacts
More answers to your device-specific questions are usually just a few quick Google searches away, for ex:
How do I replace the default ringtone on my Galaxy S9?
How do I set a custom notification sound on my iPhone 8?