hi guys this is my first ever try to wire up some stuff in my van..i have Alpine MRP-F240 4-Channel Amplifier..alpine ute 72bt head unit..2 alpine 6x9.. now i have conected the amp to the head unit..conected the sub and rear speakers..only thing is i get device error and it cuts out if i have the volume over 10..is there an idiots guide to wiring up a system? kind regards and sorry for my stupidity