To open settings window go to Tools -> SIDGIN -> Google Sheets -> Settings.
Load Sheets On Game Start - this setting is necessary for the system to download data from Google Sheets before launching the game.
Tables is a list of links to Google Sheets tables.
Set table name and push on plus button.
If you want logout from Google account go to Settings and click on button "Reset Authorization".
If you want use your Google Api Application, follow steps.