Recommended Products allows a merchant to present additional products to users after they've added something to their shopping cart.  There are a couple of ways to activate this feature.

After logging into the ecommerce control panel

1. Navigate to Operations > Settings > Products (tab).  Under the Location to redirect after adding products setting, set the location to be (Figure A):
   1. Upsell Flow
   2. Cart (then follow step 3)
   3. Checkout (then follow step 3)
   
   
   
   Figure A
   
2. Then assign Recommended Products through the Related Products section.  More information found here.
3. If you chose "Cart" or "Checkout" in step 1, then navigate to the appropriate page within the Predefined Pages section of the control panel (Pages > Predefined Pages > cart.aspx/checkout.aspx/1checkout.aspx)
4. In either the header or footer of the page you can add a Recommended Products section with the nsScript <ns:RecommendedProducts /> (Figure B). This will then display Recommended Products for any product added to the cart. 
   
   1. If no Recommended Products are associated with the product, nothing will display.
   
   
   
   Figure B
   
5. If you selected Upsell in step 1, then any time you add a product to the cart the user will be redirected to the recommended-products.aspx page.
6. A merchant can customize the header and footer of this page by accessing the Predefined Page (Pages > Predefined Pages > recommended-products.aspx)

Then to test, simply add any product with a Recommended Product assigned to the shopping cart.  The page should redirect and display your Recommended Product(s).