This is important as it affects the whole campaign experience.
Three points to remember.
1) Always make sure the script runs when you start the campaign. When you start the campaign first time it should autoactivate and add one denarius to your treasury.
2) Each time you reload the campaign (or if it doesn't autoactivate the first time), click on a settlement then on the face of the advisor that pops up. Again you'll see one denarius added to your treasury.
3) If you decide to switch campaigns to a different one, you must exit the whole game (not just the campaign) and relaunch otherwise the script won't run.