It might be that none of this will work. The campaign edition has that name because they explicitly say they are not supporting mods and multiplayer.
From Finder, Control-Click the file and select “Get Info” from the pop-up menu.
The bottom pane of the window that comes up should be “Sharing & Permissions” with two columns, “Name” and “Privilege”. You should see yourname (Me) as the first or second line. You want your corresponding Privilege to be “Read & Write”.
If it is already “Read & Write”, then I cannot help you with this particular error message. If it says “Read Only”, then click on that and change to “Read & Write” and close the window. You might be prompted to enter your admin password.
The path to my MODS folder is: Documents > Aspyr > Sid Meier's Civilization 5 > MODS
But I am not sure why you were looking for a “containers” folder?