There are factors you'd want to consider before reconciling your bank account. Firs, you'd want to make sure to review your accounts in QuickBooks to ensure the transactions match the real-life bank and credit card statements. I can guide you in doing so.
Here's how to reconcile your bank account:
Go to the Gear icon and then select Reconcile.
On the Account drop-down menu, select the bank account you want to reconcile.
From the Actions column, click the View Register link.
Click the Reconcile button.
Check the Last statement ending date. Make sure your bank statement starts the day after your last reconciliation.
Review the Beginning balance. Ensure the beginning balance in QuickBooks matches the one on your bank statement.
Enter the Ending balance and Ending date written on your bank statement.
When you're ready to start, select Start reconciling.
Also, I've added these video tutorials to help you with the reconciliation process: