Hi. I, too, am new to guitar playing and am rather intimidated by much of the equipment. But what I was told to do, is to use the USB audio interface device that I bought. It has two audio-in jacks (I think that's the right word). I am supposed to plug the amp into one jack and my laptop into the other jack. The laptop has the backing tracks stored on the hard drive. The software associated with the USB audio interface will bring in the B/T and the live guitar at the same time.
I haven't had the nerve to actually try this. If playing guitar with backing tracks were a horse race, then the backing track left swiftly out of the gate when the bell rang, but I stumbled and am several paces behind.
Kind regards,
Donna