May I ask what specific help you need about reconciliation. This way, I can provide accurate steps to help.
However, if this is your first time reconciling your bank account in QuickBooks Online (QBO), you'll need first to review the opening balance before doing a reconciliation. Once done, you can now start reconciling together with your bank statement handy.
Go to the Accounting menu on the left panel to choose Reconcile.
This will take you to the Reconcile an account page.
Choose which bank/credit card you’re working on by clicking the drop-down for Account.
If you’re reconciling an account for the first time, enter the Ending balance and Ending date. The data needs to match the balance of the actual bank data.
Once you’re ready, hit the Start reconciling button.
Review the entries on the bank statement and look for the same data in the Reconciliation window.