Thanks I have finally been able to do it. Now, I need help about how to properly cook the mod. The way I did it, (out of the mod kit since the button doesn't not work); there is only one pak file in the end. When checking at other mods, I notice there are like 3 files in the mod folder and also 2 pak files. I managed to launch the mod by manually placing those files, but that's another doing this online. I will put this mod on nexus this way...

Before you create the solo session, on the right under saves it has a tab for mods

Hi everyone,
I can now launch the game on my machine, but I still don't know how to load a mod during a solo session.
If anywone is willing to help, thank you