To do Category Mapping:

1. Go to Prestashop Admin Panel
2. On the left navigation bar, place the cursor on Facebook Integration and you will see it getting expanded as below:
   
3. Click on Category Mapping. 
   The page as shown below:
   
   1. In this section, you can see your Prestashop store category map with Facebook category on the right side.
4. For category mapping, click on ‘+’ button as shown in the above figure:
   
5. In this section
   • Here you need to map your prestashop categories with Facebook category.
     (Note: Module uses the default category of product to assign products in profile.)
   • Select the options Collapse All, Expand All, Check All, Uncheck All to perform these operations to select the directory.
   • Select the category of Facebook on the right side.
6. Once you have complete your category mapping, click on ‘Save Button’ to save the above information.