I like to practice my guitar playing along with my MP3 player but find that I can't get a good mix between guitar and song or vice versa. I'm a total noob when it comes to using mixing boards. I have a Mackie Mix Series Mix8, HXStomp, Fioo X5 lossless mp3 player. How would I connect my X5 player and HX to the Mix8 so that I can control the mix for volume of the music and the guitar? I listen through headphones.