The account owner of the google apps script would need to create a spreadsheet for each user, and provide the spreadsheet file ID to each user. All the spredsheets would reside on the account owners google drive.
Or, as previously suggested:
The account owner of the google apps script would need to create a spreadsheet for each user, and provide the spreadsheet file ID to each user. All the spredsheets would reside on the account owners google drive.
Or, as previously suggested: