Music as a ringtone on my iPhone?

I want to add a song I have purchased on my iTunes account and have in my library as my ringtone on my phone. I have youtubed some tutorials on how to do it and on the many that I have watched, one of the first steps is to click on 'ringtones' on my iTunes on my computer. Under the 'Library' section is where it is showing to click 'ringtones'. I however, on my iTunes account, do not have this 'ringtones' option! I'm so unsure how else to do this… Any help?

Try to sink your iPhone to your computer, then add the ringtones to your phone.