If you are using a different design-tool besides Macromedia Dreamweaver or UltraDev refer to the next section dealing with your particular design-tool.
On Dreamweaver and UltraDev the process of installing the extension onto your computer and adding the extension to a particular website that you wish to configure the plugin for is a SINGLE STEP. Follow this procedure each time you wish to add the plugin to a website address.
Note: A copy of the readme will be added at Your_Web_site_Folder\sc-bin\AuthorizeNet_Help