It won’t work – GarageBand Review

I have tried a bunch of times to make a ringtone for my phone by using another app and exporting it to this app but each time I do it says “adjust length” when the video is 27 sec long. AND it says there is another audio like that whenever I have no other audios in there. AND it says “core audio not available” I have been trying to do this for almost and HOURRR.
Review by Abby >:3 on GarageBand.