Before we start, could you please tell me if you're attempting to automatically match payments with deposits? If this is the case, this feature is not yet available in your region.
If you've connected your bank account and trying to match bank transactions with QuickBooks Online transactions, I'll show you how to do it.
Here's how:
Go to Banking.
Choose the account tile you want to review.
Select the For review tab.
If QuickBooks finds a matching transaction, click on Match in the Action column.
Keep in mind that the fields you see will vary depending on the transaction you are matching. You can expand the view and see the details by clicking on the transaction. I'm also adding this article for more information: Categorise and match online bank transactions in QuickBooks Online.