Product Groups are useful because they are a way of sorting the Products into groups, making it easier to search for Products and also to use in reporting.

To see this you will need to select the Menu option: Setup > Products > Groups

To create a new Product Group click

When creating the Product you will need to select the Group you have created and this will mean in the Order you can filter by the specific Group and get all the Products linked to that.

Here is an example of how it looks on a order -