Copy your code and put it into the "ecwid ID" parameter in every ECWID extension widget you place into your page; it should be a number.
List of Ecwid extension available:
ECWID - Product Browser Widget
This is the main container and it is mandatory; this will contain your products, categories, search results, the checkout options and more.
ECWID - Bag Widget
This widget contains the Shopping Bag; when viewing products you can Drag & Drop them to the bag for adding them to your basket.
ECWID - Categories Tabs Widget
Permits you to see the list of categories using a tabulator
ECWID - Categories Menu Widget
Permits you to see the list of categories using a vertical layout
ECWID - Search Box Widget
Permis you to search for a product
ECWID - Store Settings
Permit you to change some options like the language in your store.
PS. You need to use the UTF8 encoding or you may encounter problems when using languages different from english