Ok here's the steps to install it properly:
1)download the files
2)combine them
3)Install SS 6.4. Just to be sure, try it once so if it works.
4)If it works, then merge the downloaded data folder with the SS 6.3 folder (which is also the SS 6.4 folder)
5)Say yes to all replacements.
6)Done
Problems:
When you click on the setup.exe to change something (changing AI, permanent arrows, etc). The setup will upload the original files of SS 6.4 and replace the submod files except the battlemodel and export_unit/exportbuilding files in the text folder.
When you change the setup, you have to reinstall the submod following the same steps (merging, say yes to all, etc.etc.)
If it still doesn't work. Reinstall SS 6.4 clean. Then insert the submod.
Note:
Not compatible with disable RR. (Later on yes)
Only Early campaign only (later on Late campaign)
not compatible with any submods (especially MSC)
1TPY (later on 2TPY)
Hope this will help people.
On a side note. I've seen that the first part was downloaded more than the second one, you need both parts, if not then you'll have problems with the game.