In the Dreamweaver MX menus, choose Site > New Site and the following dialog shown below will appear, if this does not show the same dialog as in the image select the "Advanced" tab and it should look like the image, give your site a descriptive name and for the "local Root Folder" browse and select the folder your site files should be stored in.
Next select the "Testing Server" and the dialog should then look similar to the image below, choose your preferred Server Model, this screenshot shows ASP.NET C# being selected but you can use ASP.NET VB if you prefer as it will make no difference to the Cart extension or this walkthrough, this example also shows the "Access" option being set to Local/Network, again this can be set to alternative values if you prefer.
Once you have finished setting your options you can click the "OK" button and your new Dreamweaver site is defined, you should now copy the files from the downloadable template site into your site folder, this will give you the basic building blocks to add the cart controls to.
Next: Define your site folder as an IIS application