I know this may be a beginners question but I am fairly new to recording so I bare no shame lol. I was talkin to the support people for my interface (focusrite scarlett solo) and the guy told me in order to plug my amp into my interface I needed to use either line out left or line out right. I had to make sure my interface was on line instead of instrument, plug the guitar amp into my interface and then my guitar into the amp. I did this and it wouldnt record and I could hear myself outta the amp instead of thru the headphones plugged into my interface. I have a Fender G-DEC 30 guitar digital entertainment center amp if that matters.