Here's a very simplistic introduction to the loop pedal that I love to use. The Boss RC-300 Loop Station. For anyone wanting to transform an acoustic song with a looper, here's how I like to do it. In case you get bored of listening to me, here are some key points:
The song before the looper: 02:30
The song using the looper: 12:18
How the pedal works: 04:16