I have Europa Universalis with patch 1.19. I am also using the extended timeline mod. This mod adds a lot of buildings to the game. Unfortunately, it seems impossible to build more than 12 buildings in a province. I know that there is a mod which gives 16 building slots. I do not use steam, so, I cannot download the mod. Is there a way to edit the game files and give me more building slots?
What you are trying to do is, as of version 1.19, not possible I fear.
You can use this site to straight download Steam Mods for installing it manually.
The mod might easily be compatible with 1.19 since unless the building slots system was changed since that patch (which I doubt) the only difference is the verison specified in the .mod folder.
I would also like to add that we discourage piracy.