I am setting up Odoo for an existing business and need help with entering initial stock valuation, which the company is intended to use FIFO with Automated inventory valuation: The following is the scenario details:

opening stock (we are ok with averaging out for the initial stock).

e.g.  there are two products:

Coke  6 pcs (@ 2.00 USD) = 12 USD total  (belongs to Drink product category)

Apple 5 pcs (@ 1 USD) = 5 USD total (belongs to Fruits product category)

How do I enter those initial stock valuation so that after entering opening initial balances,

when I sell 

1 can of coke, it will deduct 2 USD from the inventory valuation (as COGS)

and in the future, when I purchase 

coke and apple it will automatically take care of costing (i.e for coke the cost will be 2 USD until it runs out the 6 pcs and then whatever the cost I bought)

I see the following links 

https://www.odoo.com/forum/how-to/warehouse-management-6/how-can-i-record-my-initial-inventory-55257

and I don't know how to link the opening balance account with the inventory (e.g. how do I link 6 cans of coke with the opening balance of USD12 ) ?

Thanks in advance.