To get the track as a ringtone, click the "download ringtone" button next to the tracks's title. Depending on your browser, that link will either automatically download the file to your computer or send you to a page where you can download the file.
Once downloaded to your computer, you can transfer the ringtone directly from your computer to your phone through Bluetooth, USB, etc. Every phone has a different method for downloading and using ringtones (for instance, iPhones requires transfer via iTunes). Please consult your phone's instruction manual if you have any questions.
The ringtones have been encoded in the most widely accepted format, mp3. File formats and transfer protocols will depend on your phone and carrier. If necessary, go to http://www.mediaconverter.org/ to convert your ringtone into other popular formats.