I was hoping to combine/merge new submissions into an existing sheet.

I was hoping to combine/merge new submissions into an existing sheet. This just creates a new sheet. It doesn't let me enter a worksheet name. Is there any way to accomplish this?
Use an existing sheet – select a spreadsheet from your Google account and enter a worksheet name.

Hello Dawn,

Thanks for reaching out to Jotform Support. Yes, It is possible to add your form submission data into the existing google sheet in your account. To do that please follow the steps below and screencast:

• Click on the Setting on the Orange navigation bar at the top of the page.
• In the menu that opens on the left side of the page, click on Integrations.
• Search Google Sheet in the search panel.
• Select the Gmail ID in which your Google sheet is present.
• Choose Use an Existing Spreadsheet option
• Search spreadsheet name in the search option. 
• Select the fields that need to be uploaded on the spreadsheet and click on the Save button to save the changes.

For more information please check this guide on How to Integrate Forms with Google Sheets.

If you need further assistance, please let us know.