Cura is a program that reads in 3D models and prepares them for printing. If it is not installed on your computer it can be downloaded for free. While there are Windows, Mac, and Linux versions there are problems running it on Raspberry Pis. A Raspberry Pi can be configured to access Cura running on another computer in the local area network. Contact your local tech support if you have any questions or problems.
Below is a collection of short videos explaining how to use Cura. Full documentation is available here.