Hi,

Create a Product Variant for the Box

Create a new product variant: Go to Products > Products and click "Create" to add a new variant.
Name and describe the variant: In the product form, give it a clear name like "Box of 5 Shirts" and include its description (e.g., "5 shirts in a branded box").
Set the Unit of Measure (UoM): Choose "Box" as the UoM. This tells Odoo you're selling the product in boxes, not individual shirts.
Set the BOM (Bill of Materials): In the "Components" tab, add the specific shirt product as a component. Set the quantity to 5, meaning each box will contain 5 shirts.
Calculate the cost: Based on your shirt cost and packaging material cost, calculate the total cost of producing the box. Update the "Cost" field in the product form.
Set the selling price: Decide on your desired profit margin and set the selling price for the box of shirts.
Publish the variant: Save the product variant and make it visible on your e-commerce website.

Hope it helps