Let me break down your questions to make sure I'm able to address everything, KA2022.

When you enter a transaction before downloading the bank transactions, you'll need to do it with the existing transaction.

Here's how:

1. Find a downloaded transaction with the Match option in the Action column.
2. Note the Date, Description, Payee, and amount spent or received.
3. Select the downloaded transaction to expand the view.
4. Review the Matching records found in QuickBooks. This is the possible matching transaction you already entered in QuickBooks.
5. Select the link next to each match to get more details.
6. Make sure this is the correct match. In particular, review the Deposit to, Payment method, or Bank account fields on forms for the existing transaction in QuickBooks
7. If this is the correct match, close the open transaction.
8. Click Match.

Here's an article that you might find helpful when matching and managing your downloaded transactions: Categorise and match online bank transactions in QuickBooks Online. 

Moving on to your next question, if you're trying to match a downloaded transaction that was a lump sum payment for multiple invoices, you'll want to utilize the Undeposited Funds account to make a deposit. 

Here are the steps for recording the payments to Undeposited Funds:

1. Go to the Plus icon.
2. Select Receive Payment.
3. Choose the Customer, Payment Date, and Invoices that are being paid.
4. Select the Undeposited Funds to account in Deposit to.
5. Click Save.
   
   

If the invoices are for multiple customers, you will need to receive payment for each one and deposit them to Undeposited Funds. 

Now it's time to make the deposit for these funds, here's how:

1. Click the Plus icon.
2. Select Bank Deposit.
3. Choose the payments that make up the deposit.
4. Select the Date and Account.
5. Click Save.
   
   

More information about making bank deposits can be found in this article: Record and make bank deposits in QuickBooks Online.

This deposit will now match the lump sum payment for several different invoices. 

For additional resources about managing your banking transactions, you can check out the topics from this link: Find help with bank feeds and reconciling accounts for QBO.

Please let me know how else I can help you with your bank transactions by adding a comment below. Have a good one!