Using this dialog you can add items, i.e. products offered in your on-line store, to the current order. The filter above the list allows you to view only products matching certain search criteria (Product name, Product number or Department).
To add a single item, click the respective product in the list. To add more items at once, enter the required quantity in the Quantity column and click Add to cart. Please note that you may need to specify product options (if applicable) before inserting the given product to the shopping cart.
More resources concerning products can be found in E-commerce Guide -> Managing your store -> Products.
Further information about orders can be found in E-commerce Guide -> Managing your store -> Orders.