I did not really get your question, please provide more details.
TabShop Google Spreadsheet works like this:

• Select your Google account and authorize the access when asked to.
• Select a spreadsheet and the spreadsheet will initialized with the necessary worksheets
• Enter the stock worksheet and enter your product stock
• Enter the tax worksheet and enter at least one tax rate that you are using within the stock sheet
• Enter the discount worksheet and enter at least one tax rate that you are using within the stock sheet
• Enable automatic invoice sync within TabShop Google Spreadsheet settings
• Checkout invoices and you will see the invoices automatically coming in within the selected Google Spreadsheet
• Mind that the product stock amount is NOT automatically updated as this is not directly possible with Google Spreadsheets

You can find a tutorial here: