What do they mean when they say channels? And where do i get the wires to hook up the amp to the battery. Thanks

 

A channel is an output to speaker(s). A monoblock amplifier has one channel. A two channel amp, has two channels, etc. If you want to power the two door speakers in stereo, you will need two channels to acomplish the task.

Most any stereo shop has power cable available for amplifiers.