Hi Feras,
What you are looking to make is actually called a Many to Many relationship between orders and items. This is done by having a set up like:
one-many orders-> (New Join Table-called line items or order items for example)
one-many items-> (New Join Table-called line items or order items for example)
What this allows you to do is have a relationship where you select an order and then select an item on each line item record and then add quantity and any other specific info for each line item. This allows you to get the functionality you are looking for that an order can have many items under it pulled from a menu of items. You can learn more about Many to Many relationships
right here in University to get you started under our complex relationships lesson. If after reviewing the lesson you would like some help putting it into your own application you can also always reach out to our Care team for some one on one help building that relationship via a support case by clicking Support where it appears in the upper right hand corner here on the Community or when signed into Quick Base by clicking the question mark (?) icon that appears in the upper right hand corner and selecting "Manage Support Cases" to create a new case. I hope the suggestion is helpful Feras.
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Evan Martinez
Community Marketing Manager
Quick Base
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