How can i Add the beginning balances of my customers one by one

i would like to add the beginning balances for my customers as other opening balances, but the accounts receivables doesn’t appear in the opening balance sheet while i have some customers.

Once you choose a start date, enter any open invoices pre-dating that (via Sales Invoices) making sure to date them prior to the start date. These will ‘build’ the opening receivables balance for each customer and the total of them all will show as the total ‘opening balance’ on the opening balance report.