Instructions
Navigate to "\My Documents\Electronic Arts\The Sims 3\" on your hard drive. Create a new subfolder within this folder by right-clicking and selecting "New," then "Folder." Name the folder "Mods."
Download the resource.cfg file from either the Techno360 or Slinky and the Sims sites in the resources listed below. Save the file in the previously created "Mods" folder.
Create a new folder called "Packages" inside the "Mods" folder. When downloading a new mod for "The Sims 3: Ambitions," save it inside the "Packages" folder. The next time you load "The Sims 3: Ambitions," a message will appear letting you know which mods you have installed.