I can help add some details, @yodankful.

When connecting your accounts to online banking, you'll need to check with your bank how they send the transactions. If the transactions download to one account, connect only the parent account. If the transactions download to the individual accounts, connect the subaccounts and not the parent account.

Once it's time to reconcile, you only need to reconcile the parent account since all the transactions in the subaccounts roll up into it. Let me refer you to this article for more information: About bank or credit card subaccount setup.

I'd like to include this related post from one of our Community backers: https://quickbooks.intuit.com/learn-support/en-us/reports-and-accounting/how-can-i-fix-my-credit-car....

For other related articles, you may visit our site for tips and helpful guide: Reports and accounting for QuickBooks Online.

Let me know if you have additional questions about setting up your accounts. I'll be around to help.