For Nexus 6p just copy the ring to Ringtone folder in main directory and you can see it in sounds from where you generally change your Rings.

Super beschrieben , aber es fehlen zwei Details: Es mόssen unbedingt mp3-Dateien sein, andere gehen scheinbar nicht, und Klingeltφne unter "Ringtones" abspeichern!

Transfer Audio Files from a Windows Computer:

1. Establish a USB connection between the Nexus 6P and computer
2. On the home screen, swipe the “Notification” bar down
3. Ensure the phone is connected as a “Disk drive”
4. On the computer, launch an Explorer window
5. In Explorer, locate the desired media files on your computer
6. Copy the files, and navigate to your phone storage
7. Paste the files on the phone, preferably in the “Media” directory, and “Alarms” / “Audio” / “Notifications” folder(s). NOTE: If one or more of these folders are missing, you can create them manually
8. After the transfer is complete, eject the phone storage by clicking the “Safely Remove Hardware” icon in the system tray
9. Once ejected, safely disconnect the phone from the USB connector

Set a Custom Ringtone:

1. Open the apps drawer
2. Access “Settings”
3. Scroll to “Device” and tap “Sound”
4. Under “Call Ringtone & Vibrate”, tap “Phone ringtone”
5. Select the desired ringtone and tap “OK”
6. Optionally, enable or disable “Also vibrate for calls”

Change a Contact’s Ringtone:

NOTE: Custom ringtones cannot be assigned for contacts stored on the phone’s internal memory or the SIM card.

1. Tap “Apps” on the home screen
2. Launch “Contacts”
3. Select the desired contact and tap the “Edit” icon
4. Tap “Menu” > “Set ringtone”
5. Select the desired ringtone and tap “OK” to confirm

Change the Notification Sound:

1. Go to the phone’s “Settings” menu
2. Scroll to “Device” and tap “Sound & notification”
3. Under “Sound”, tap “Default Notification Sound”
4. Select the desired notification sound and tap “OK”