I have just begun to use Quickbooks online.  I would like to set up bank accounts in several different currencies.  Similarly, I need to set up Accounts Payable in a couple of foreign currency.

Of course, in each case, I need to define the opening currency balances (as at 31 March 2020) in account.  That's straightforward.   But I also need to apply the foreign exchange rates which prevailed on 31 March.  More accurately, I want to apply the foreign exchange rates which I used (in accounts created in accounting software now supeceded by QBO) on 31 March when valuing those balances in my home currency.   Once that's acheived, I can bring the accounts up to date and, using a home currency adjustment, value the up-to-date balances using QBO exchange rates.

So, in short, this is a question about imposing the home currency valuations of foreign curreny balances