It is very easy to change the category that a product is listed to and you can perform the task directly from the dashboard of the E-Commerce Configuration.
Navigate to the Webstore Products page from the main navigation.
Use the filters on the left-hand navigation to browse to the product group that you want to change the category of.
Highlight the row and on the top navigation area click the button labeled “Recategorize”. Keep on clicking through the category tree digging deeper and deeper until you find the category you wish to have the product listed to. Click “Select” once you get to the desired category.
Make sure you click all the way down to the category that you want the product listed to. Don’t settle for the most top-level category. If you want to categorize Brake Line Fittings, don’t just get to Brakes or Brake Lines and then quit. Click all the way down into Brake > Brake Lines > Line Fittings.