There are books writing about this subject, but this class will focus on using Eagle for a typical small run prototype PCB construction. PCB's are a complicated custom connectors moving electrons to only the places you want them.
There are several steps to taking a idea and creating a PCB for it.
There are options for each of the steps, here some examples:
Download PCB design -> modify -> CAM -> Generic PCB service
"idea" -> CAD - > CAM - > Mini-Mill -> post work
"idea" -> CAD - > CAM - > photo etch -> post work
1) Install Eagle CAD
2) draw the schematic
3) generate / layout the PCB
4) Making / Having it made