First off, let's describe what is a multi-level product is.
A multi-level product is one that contains a product within a product. For example, some businesses will make "intermediates" or "premixes" that are then used as an ingredient within another product.
Zubi manages this situation by allowing products to be LINKED.
Linking a product effectively means it has been converted back into an ingredient that you can then use in a recipe within another product.
You can use the Link Ingredient option either when creating (adding) a new product or when you are editing a current product.
To "Link" a product and convert it into an ingredient simply tick the box at the top of the screen: Create ingredient from this product?
Once you have linked a product Zubi will make a copy of the product and store it within the ingredients section.
It will have the same code as the original product but will have an " i " added to the end of the code.
When you open the product you'll see the ingredient it's linked to is shown in the top right-hand corner.
You can then add the linked product / ingredient to a recipe in the same way you would do for any other ingredients.