To import to an existing table, you need to start from within the table itself. Click Actions → Import → Import from CSV from inside the table you want to add data to. [1]
The "New blank table" option appears when you start the import process from your workspace home using Create new. To see the "Add to existing table" option, navigate to your target table first, then use the Actions menu to import. [2]
If you still need help with importing your CSV data into an existing table, I’m here to assist. Would you like to provide more details about what you’re trying to achieve with your import?