I'm here to help you with undeposited funds, jane34.
The Undeposited Funds account is the temporary account that holds the money until you deposit it.
When you download the transactions, it won't be added automatically into your register. You still have to add and match them into the existing transactions you created in QuickBooks Desktop. Please refer to this article: Add and match Bank Feed transactions in QuickBooks Desktop.
I have an article here about reconciling an account in QuickBooks Desktop.
Please comment below and tag my name if you have more questions. Have a great day!