Reply to Free software + Midi Fighter Spectra + Mappings

Does anybody know how to make the Midi Fighter Spectra and Mixxx work? It says that the spectra is compatible but I need to find a mapping and I have no idea where to do that.
Are there any other free programs that could work that anybody knows of?
If I need to make a mapping does anybody know where I could figure out how? Is it really difficult? Thanks All feedback is appreciated