A breadboard is a solderless electronic circuit builder - perfect for proving your concept.
Everything you need to know to get started using EAGLE.
EAGLE's thousands of library files can be overwhelming. We have more than 500 curated, proven design files for your use. 1) Grab them in GitHub, 2) drag-and-drop a ULP file into an open EAGLE schematic, or 3) find single product design files on product pages or in GitHub (note for product files: individual board files are in "Hardware" directory and EAGLE panels are in the "Production" directory).
This step insures that a manufacturer can successfully fabriate your PCB. With SparkFun's design rules files, you can check your design for errors.