How Does The Brain Sends Message To Different Parts Of Body?

The brain sends messages along the nerves, sort of like how we hear people talk on the phone, we understand and respond to what they are saying.  Same for brain, we send it a message, then it understands what we are saying and will tell whatever part of the body to do what we want it to do.  It is like small electrodes, giving signals.  Some are involuntary like the heart and lungs, just does it automatic, like being connected to phone company without picking it up and others are what we tell it to do, like dialing and telling, okay, move fingers, etc.