You post the bank entries, the AP opening balances, the FA opening balances through the general journal. How you get this data into there depends upon the details.
With the opening inventory you can enter this as a Profit and Loss or Movement journal whichever is your preference.
The posting of the journals will give you your opening balances.
I suggest you start to create them - but you obviously need to understand how the journals work to do this! Do you?