On the list of balances you see current existing balances.
You can display the details for each balance where you can see the calculation for each asset.
Define the period for which you want to create the balance. It is not possible to take the same period a second time.
If you click on "Pre-calculate" you get a calculation for the assets for selected period.
If you click on "Create balance finally" the balance will be finally stored and all transactions linked to this balance will be locked. It isn't possible anymore to edit these transactions.