In order to create a new Google Sheet connector, click on the Data icon from the portal.

Expand the Data source icon and move to the folder where you want to place the new datasource in and then click on the new Datasource icon. (Depending on your user rights this icon might be grayed-out in some folders)

Select Google Spreadsheets from the various datasources option and double-click it.

Give a name to your Google Sheet connector and then click the Authorize button and follow the Authorization flow

Once it is completed an Access token and refresh token should appear and you can click on the OK button.

You can now use your Google Sheet connector to use the sheets you have access to in your data worksheets.