Thanks for reaching out about reconciling your bank accounts. QuickBooks Online is a great tool able to help you keep track of transactions so you can make sure your bank balance is accurate in your books. I can provide some information about reconciling.
To reconcile an account in QuickBooks Online, the transactions would first need to be categorized. You would first categorize them in your books, then use the reconcile feature to make sure all of them are entered correctly and there aren't any missing or duplicate transactions. Here are some helpful artiicles about reconciling your accounts: