I have searched and tried to read a little but most of it was somewhat over my head. Hopefully someone can 'dumb it down' a little for me. My goal is to record guitar in Garageband the easiest and cheapest way possible. I have the adapter to goes from 3.5mm jack to instrument cable (pic below). I adjusted System preferences to accept line in, but when I go to Garageband and add real instrument, and use the guitar all I get is feedback and when I play it doesn't record anything. Can anyone help me figure this out. I am writing some songs and have no other means of recording them. Thanks in advance.