KiCAD is a Open Source Computer Assisted Drawing (CAD) software for designing Printed Circuit Boards (PCBs) from Schematics to Gerber Files. Its features have been enhanced through heavy development by CERN and the community. It supports up to 32 layers and has no limitation on the size of the PCB.
You can find the official website here : http://kicad-pcb.org/
First, download the correct installer for your operating system at
http://kicad-pcb.org/download/
Follow the instructions to get the program installed
The basic workflow in Kicad is split into 4 parts :
Once your PCB Design is finished, you can export it to Gerber Files (Vectorized layers) and send it to your favorite PCB maker.
While the libraries are all right for some purposes, there's an issue with many of the symbols for chips. Often these symbols have hidden power pins labeled VDD and GND, or similar. KiCAD automatically connects these together, which is bad if you want them connected to a net named something else, and even worse if there is a net with one of these names which you DON'T want connected to these pins. In addition, the naming conventions on chip pins isn't consistent, and often the chip bodies are needlessly large. Therefore, it is recommended to consider copying and editing a built-in symbol.
Many of the footprints are just fine, though some are missing 3D models. However, some common footprints, like standard types for TO-92 transistors, are missing–you will have to create them.