A dividend distribution is just a normal bank transaction that you link to a dividend payment. You can manually create the transaction from your bank account page by clicking 'Add Transaction' on the top right drop-down menu on the Bank Account transactions page, or you can distribute the dividend, import your bank statement and then link the transaction.
Manual addition:
Make sure 'Money Spent' is selected
Under 'Money Spent On' select 'Dividends: [user]'.
Select the date and enter the amount and save the transaction.
Through bank statement import:
Or, if you imported a bank statement you can click on the unexplained transaction that was the actual dividend payment and then do the same as above when asked what the transaction was for.