1. Add a Tag to a product, for example, New.
2. Go to Groups.
3. Click on Add Group.
4. Add details for the group (Name, Short Description, Long Description).
5. Go to the Rules area.
6. Add a Rule, setting the Products matching to be set to Product Tag.
7. Click Save.
8. Click on View Group.
9. You will now see all of the products inside the group which use the tag you specified, in this example New.