garage band

I'm not sure, why it is not working for you. Perhaps you expect garageBAnd to be an audio Editor, but it is not. It is a tool to mix song arrangements. The original audio files will be left untouched and combined in a new project. Then you bounce the finished song as a new audio file to iTunes or to the disk.

Did you start your GarageBand project using the Ringtone template? Then it should be easy. This template will already activate the yellow cycle region to show the 40 seconds in the cycle range. Only the part of the song below this cycle range will be shared when you bounce the song to iTunes. See the screenshot below:

• Drag the song you want to turn into a Ringtone into the track area to create a track with this song.
• Grab the left end of the song region in the track with the mouse. The mouse pointer should turn into a bracket. Drag the left border of the region inward to trim it.
• Now adjust the right end of the song region to trim it.
• Use the share menu to send the ringtone to iTunes.

Did you use "Share > Ringtone to iTunes" in the Share menu in GarageBand?

If yes, show all ringtones in iTunes by setting the menu in the upper left corner to "Tones":

if the song is really not saved to iTunes, bounce it to the disk instead as a song, then change the filename extension of the bounced song to ".m4r", for example "MyGuitarRingtone.m4r".

In iTunes use the command "File > Add to Library" to import the new ringtone.