3D printing?

Upon searching and reading through this forum i have failed to find and links or resources where i can download the files to 3D print my Hexy robot. i am very new into robotics and 3D printing. All i need is a little clarification on what exactly are STL files and what programs can i view them in and ultimately where can i obtain these files? Thanks everyone! Any help is greatly appreciated!

STL files are the files 3D printers use. If you have a printer, it should be able to open and view and print these files.

The 3D printing files are here:
github.com/ArcBotics/Hexy