Intro

Now that you have your Lulzbot Prusa Mendel printer set up it is time to print!

Getting software

Most free open-source software can be found at Github.com or by searching the software name and Github in a web search engine. Otherwise, you can find wiki pages for software on Reprap.org.
There are two basic software types you need to run your 3D printer. One is the host software which interacts with the printer sending instructions and receiving information. The other software needed is the slicer. The slicer software takes an .stl 3D model file and slices it into layers creating a .gcode file. The gcode file is instructions for the printer on how to print the 3D object. The.gcode file is sent to the printer through the host software.
For a great reliable host software get PRINTRUN. Your RAMPS electronics have already been flashed with Sprinter firmware which is completely compatible with Printrun. The file in Printrun you will need to run is pronterface.py.
There are two options for 3D model slicers. The older software, SFACT is based off of the Skeinforge slicer. SFACT can be somewhat complex but is documented well and works great. Slic3r a newer slicer is currently in early development but is working. Slic3r is a much faster and easier slicer for beginners.