Adding a secondary category to your product ensures that you increase its exposure in this way.
How to add a secondary category
In the main menu,if you click on Manage Products, and then click on the three Grey Dots to the right of the Quality Score, on the Product that you wish to add into a secondary category ,see below :
Then if you click on Edit, it will take you into the Product Editor for this product:
If you then scroll down the page, at the bottom you will see the option to Add a Secondary Category for your product ,see below :
You can now select from the drop down menus, shown above, regarding which secondary category and subcategories you would also like to add your product to.
Once you have chosen the secondary category, if you then click twice on the tab on the bottom right as shown below :
And then if you click on the button below, your changes will be saved, and your product will now also be displayed in that chosen secondary category.