When you decide you need to group certain products into a product class, first, you need to create this class.
To create a new product class:
In your store’s Admin area, go to the "Classes & Attributes" page (Catalog > Classes & Attributes).
Click the "New product class" button.
An editable field will appear on a new line in the list of product classes.
Use the new field to enter a name for the new product class.
4. Click Save changes. The newly created product class will be saved and added to the product class list.
If necessary, you can edit the product class name or delete the product class altogether.