The recommended method to install, is simply using your target website marketplace page. However, if you wish not to use concrete5 internal feature, you can follow the next instructions:
After installing the addons, a new "Addon List" block will be available. To display the package list, just add the "Addon List" block to a page. Since the retrieval of marketplace URL can be a bit slow, I would recommend to cache the output of this block to have improve the page loading time. More documentation about Concrete5 caching system can be found Here
This addon is a free addon, and does not come with free support. If you have a problem, just post a support request, we will reply when we have some time to do so.