Coolrunner II and Vivado?

I'm trying to program my coolrunner ii for a class I'm taking, but I can't seem to get vivado to let me pick the XC2C256 chipset for my project. I can plug it in, and the hardware manager sees it, but I have no idea how to get code I have written onto the device, since it won't let me select my board or chip for the project. What am I doing wrong?