There are lots of ringtones to choose from on your galaxy s6 edge, but you may find you want to add a custom ringtone. You need to make sure you have the song you would like to use already downloaded onto your galaxy s6 edge then go to the settings. Next click on sounds and notifications and scroll down to ringtones.
Once you click on ringtones you will see a long list of different options, but simply scroll down to the bottom where there should be a plus symbol. Next you should see a list of songs you have downloaded onto your galaxy s6 edge, and you just need to choose the song you would like to add as your ringtone and you will be all set.