All Android devices come with their own set of sounds for ringtones, alarms and notifications. If you want to use custom sounds that you have found, you will need to follow these steps to keep things working in an efficient manner.
1. Connect your device to your computer using the USB cable.
2. When prompted by the device, mount the SD card to the computer.
3. In the root of the SD card, create three (3) new folders: ringtones, alarms, and finally notifications.
4. Copy all of the sounds that you wish to use from your computer to the associated folder (created in step 3) on the SD card.
5. Unmount the device’s SD card from the computer.
6. To assign one of your new ringtones or notifications to your phone, click the device’s Menu button. Tap Settings and select Sound. Select either Phone ringtone or Notification ringtone (depending on which you are assigning) and select the new sound from the list. To assign a new alarm sound, open the Clock app and select an alarm. Tap Ringtone and select your new sound from the list and then click the Done button.
While some versions of Android allow you to long-press on sound files and set them as ringtones, this can end up being quite a mess. This is because your sound files could be in a number of areas on the phone. By using the three directories named above, you can easily manage and backup your custom ringtones.