What you are trying to accomplish will take a fair bit of custom coding due to the many to many relationship that is used instead of the 1 to many from the tutorial.
the the first recordset would join the ps4_products and ps4_productcategories tables:
SELECT ps4_products.*,ps4_categories.CategoryName
FROM ps4_products
INNER JOIN ps4_productcategories ON ps4_products.ProductID = ps4_productcategories.ProductID
the second would join all 3 record sets together.
SELECT ps4_products.*,ps4_categories.CategoryName
FROM ps4_products
INNER JOIN ps4_productcategories ON ps4_products.ProductID = ps4_productcategories.ProductID
INNER JOIN ps4_categories ON ps4_categories.CategoryID = ps4_productcategories.CategoryID