...
We create a Production document with the type of Disassembly operation.
Go to -Production - Productions.
You can use this form to create a new Production document to register the disassembly of specific items.
On the Main tab, you can provide general information about the document.
First, select Disassembly as the transaction type – this will make available the appropriate fields.
Specify the warehouse where the item is listed.
...
Create two new items.
In the Quantity column, you can specify the item quantity and in the Unit column, you can select an UOM for the item
The Cost Percentage column shows the proportion in which the cost of finished goods is shifted to the resulting items. 
Post and close.
Generate a report to check your actions.
...