Add the directory of the OpenScad executable to your search. For Windows OpenSCAD-2012.02 or later is required. For Linux it will need to be OpenScad-2011.12 or later.
machine_name can be mendel or sturdy. To make your own variant copy scad\conf\mendel_config.scad or scad\conf\sturdy_config.scad to yourname_config.scad. Then run make_machine yourname.
To view the model of the whole machine, open scad\main.scad. It will take several minutes to render (about about 8 miniutes on my computer) but after that you can pan and zoom it at reasonable speed and changes takes less time to render. (Note: main.scad will only render correctly if conf\machine.scad exists, which is created by the make_machine.py script.)