The ZTE Nubia Z17mini sports a microSD (TF card) memory card reader. If your laptop or personal computer can also read that card format (Most notebooks are so-equipped), you should be able to transfer music files
The ZTE Nubia Z17mini is a smartphone. Most smartphones should let you save any mp3 song available online by touching and holding your finger on it and selecting 'save.' Once a music file is stored on your library, touch-and-hold it and choose 'assign' in the contextual menu.
The ZTE Nubia Z17 Mini is an Android smartphone and the Android market offers a bunch of free ringtone apps such as MP3 Ringtone Maker, Zedge and more.
Here are links to some of the free ringtones (compatible with your ZTE Nubia Z17 Mini) we offer:
Free Horror Ringtones Free Tropical Ringtones Free Ringtones-a-gogo Free Techno Ringtones Hear All Our Free Polyphonic Ringtones