If you're trying to add another item for Diwali Gift Box with existing five products on your inventory, here's how you do it in QuickBooks Online (QBO):
Go to Sales.
Select the Products and Services tab.
Choose the Diwali Gift Box item and click Edit.
Under Quantity on hand, click the link for Adjust: Quantity.
In the Inventory Quantity Adjustment page, add the new quantity of the item under the NEW QTY column.
Click Save and close.
If it's your first time to create the Diwali Gift Box on your inventory, you can simply create an item for it. I'll show you how:
Go to Sales, then Products and Services.
Select New or Add a product or service. Then select Inventory.
You can enter 5 as the Initial quantity on hand and fill in the As of date. Enter the necessary information.