How to set a ringtone on my iphone?

I have a ringtone maker app called MakeTones that saves the ringtones to the app, and they show on iTunes when I bring up that app, but I can't seem to figure out how to set them as a ringtone.

If it matters, it's an iphone 4.

Connect your iPhone to your computer, bring up iTunes and navigate into your phone. There should be a section that says 'Sync all Ringtones' or you can check the ones you want. Then, make sure to finalize by clicking on SYNC. Your ringtones should then be in the Settings of your phone.

Right click the song you want, and choose the edit option. Go to the tab where you can choose when the song should start/stop. There's a 40 second limit so you can't set it long. After you choose the time, close the window. Right click the song again and choose the Create AAC Version. After that is done, copy and paste the edited song to a folder. Change the.mp3 or whatever it's called to.m4r once that is done, you can delete the old version and open the new one on iTunes. You won't find it in the regular music section. It will be in the ringtone section this time and then you can just transfer it to your phone.