This video describes how to make and edit an invoice for which had combo items together with Add-on items.
Thsi video will expalin what are the steps that you need to take in order to make your combo item Add-on compatible.
This video will describe how you can make an invoice for combo items.
This video will describe hwo to define a Combo item in HDRestaurant, also will describe how to create a quick item collection from item manager.