This documentation is not using the current rendering mechanism and is probably outdated. The extension maintainer should switch to the new system. Details on how to use the rendering mechanism can be found here.
Install wt_cart with Extension Manager¶
Open the extension manager, download the extension “wt_cart” and install it. If you haven't already installed powermail you'll be asked to do it during the installation process of wt_cart.
There are no additional settings you can change within the extension manager.