Combining more than one item as a recipe to create one new item is referred as Assembly or Manufacturing of goods. Promotion refers to making two or more items as one item a selling those items as one item.

Example : Assembly

We need : Dark chocolate(50gm)-A101 Milk chocolate(50gm)-A201 Nuts(25gm)-A301 Dates(25gm)-A302 All these items are combined together to make one item AAA001.

Example : Promotion

One or more item is grouped and sold as one item to promote one item. Prices of all the items combined will be added and updated as cost of the promotional item. If we buy 1 pack of dark chocolate, one milk chocolate is combined with this pack and will be sold as one unit.