CE4 Cart is not a Lightroom plugin; it's a web application that you need to install online, as a part of your CE4-based website.
CE4 Cart also requires installation of TTG-BE, also included in your download. From a high-altitude view, setup is a two-part process:
To begin, setup TTG BE.
Afterward, return to this page to continue CE4 Publisher setup.
Copy the /cart/ folder from the downloaded CE4 zip file (e.g. CE4-Cart-305.zip or newer) into the /ttg-be/ folder online:
Next, you should create a template using CE4 Gallery. Select a handful of images in your filmstrip to help with design visualization, configure the gallery to your liking, then export. The exported template will not need the selected images, however, so feel free to de-select all images from your filmstrip before export to minimize the template's footprint; the template will upload faster, and take up less space on your server.
Upload the exported template into:
For example, you might have this, where “cart-template” below represents whatever name you've used when saving your template:
The templates found in ttg-be/templates/gallery can function for various purposes: as Publisher album templates, as the Cart template, and as the template for the Search page. You should always have at least one template installed, and it's okay to use the same template for all of the above if you so choose.
Login to the TTG-BE admin, then navigate to the Cart admin via the Dashboard menu.
Under the Settings menu, select Cart Settings. Here you may configure various aspects of CE4 Cart, the first of which should be: under Personalization, please select a gallery template for use.
The Turning Gate
Creating webbly, wobbly, Lightroomy things since 2007.