At the product field groups tab, you can manage you current product field groups, create new groups, edit or delete them.
The product field groups form:

The product field groups list shows detailed information about your current product field groups, including the group name, if the group is globally available or for certain vendors only, if the group is only valid, if certain categories are chosen at the product details page, and if the fieldset is a default field set or not. It also shows, how many custom fields are currently in that group yet.
To edit a certain product group click on an item in the list and the product group page will open, where you can edit all details about your product group.
To create a new product field group, click on the “Create Product Field Group” button and the product field group page will open.
Several other functions are available through the action icons on the right side of the list. Click on the edit icon to edit a group, click on the delete item to delete a group and all it’s fields.