Installing a New Add-on
In Mathematica 3.0, an add-on is a directory (folder) containing a collection of files that may include Mathematica code (a package) in .m or .mx files, notebooks, MathLink programs, and configuration files. (The terms add-on and package are often used interchangeably.)
Add-ons can be installed in either the Applications or Autoload subdirectories of the AddOns directory. Add-ons installed in the Autoload directory are automatically loaded when the frontend and kernel are started (see below). Add-ons installed in the Applications directory can be loaded manually when needed.
On multi-user systems, you can install an add-on either in the central Applications or Autoload subdirectories or else in the corresponding individual user's Mathematica directory.
Installing an add-on
To install an add-on, copy it into the AddOns directory. If it came as an installer archive, it should come with instructions on unpacking the files. Otherwise, you can simply copy the add-on directory as you would any other directory.
After installing the files, use the Rebuild Help Index command in the Help menu. This tells the front end to add any help files that the add-on may contain, and incorporate them into Help Browser's categories and index.
If any add-ons installed in the Applications or Autoload directories have help files, they will be listed at the bottom of the first column of the Add-ons radio button.
Add-ons installed in the Autoload directory will be loaded automatically on startup by both the kernel and the front end.
Ordinarily a package will declare one or more functions in the kernel. In order to save time and memory on startup, these functions are usually declared as function stubs; the full package is loaded when one of the functions is used for the first time.
An add-on may also install new menu items or evaluators in the front end, or reset configuration options in the front end. Check the documentation for the add-on to find out about any changes it makes to the front end.
Installing pre-3.0 Packages
If the add-on you are installing is not optimized for 3.0, the Help Browser will not be able to display its help files, but you can still open the help files manually by using the Open menu command in the ordinary way.
If the add-on does not contain the files necessary for it to be autoloaded, it makes no difference whether it is installed in the Applications or Autoload directory.