When you created the Fusion Table in a previous section, you used your own Google account to do so. So right now only you can access and change the Fusion Table. However, for this app to work, you need all your guests to have the ability to insert data into the Fusion Table and read from the Fusion Table.

The service account email that you created in the previous step will come in handy to achieve just that. That email is associated with your app and not any individual. Hence, anyone else using the app should be able to access the Fusion Table as long as that email address has proper access to the Fusion Table.

To enable the service level email access to the Fusion Table, go back to your Fusion Table (left open in the separate browser window/tab) and click on the blue Share button in the top-right corner. This will open the Sharing settings menu, as shown in the following screenshot.

Copy and paste the service email address that you saved earlier into the Invite people box. Make sure the button next to the box says Can edit, and click on Send.

This step ensures that any user of the app (not just you) is able to insert data into or receive data from the Fusion Table.