1. First of all you need to create a new text document. (I think what I did was go to the preference script, duplicate, delete all the text and rename it, as shown below)
2. You then need to put the file names, so in this case, _divide_et_impera_release_1.pack & _divide_et_impera_release_2.pack into the text file you just made, like so. Make sure to save the file. (I have other mods alongside, so ignore those, but you can see the general idea of how to enable mods on mac)
3. Once you've done that, put the two files into your data folder, shown here.
That's it! At the moment Grand Campaign doesn't work, however the other campaigns work great. Hopefully this helps, any questions feel free to pm me or reply here.