This feature allows you to add more than one Custom attributes groups to one product. This way products will display more groups of custom fields in products list and product details.

Enable Group Attributes feature

To enable grouping of extra fields (attributes):

1. Go to Components -> DJ-Catalog2 -> Options -> Product page tab
2. scroll down and find Group attributes part and set it to "Yes" 
3. Save options

How to add additional group of attributes to the product

Go to Components -> DJ-Catalog2 -> Products and open the product you want to edit

Click Product Attributes tab and there you'll find Field group setting where you can add more attribute groups to the product

When you're adding new Field (attributes) groups the extra fields from the group are being displayed below. Here you can modify the extra fields.

When you save the product after filling the extra fields, the new grouped attributes are being displayed on the products list:

and in product details:

 As you can see there are 3 different field groups displayed.