Edit Product Categories in Zoho Desk

Edit Product Categories in Zoho Desk

Hi. I found this: https://help.zoho.com/portal/community/topic/how-to-add-and-change-product-categories

It states: 

To add or change the existing product categories please access Setup -> Customise -> Fields -> Select the Product module -> Create or Edit fields -> Hover the mouse over the Product Category field and select the gear icon -> Edit Properties -> + Add value/Add values

However, for me it works like this: Setup -> Customization -> Layouts & Fields....and at this point I cannot find the "Product Module". I see "Products" on the left toolbar, and "Modules" there as well. But neither of these allows me to access any kind of "Edit Product Category" as in the screenshots that are posted on the linked thread above.

Could you please provide me with step-by-step instructions for finding the "Edit Product Category" page as shown in the attached screenshot from the 1-year old article that I found. 

Thanks!
Karl