To install the G-Connector add-on to your Google Sheets environment, open any spreadsheet or create a new one at https://docs.google.com, then click Get Add-ons under the Add-ons menu:
In the subsequent dialog search for “salesforce”, then click the blue “FREE” button on the right from G-Connector for Salesforce:
You will need to give certain permissions to the app in order to get it installed:
We need to be able to send email as you to send success/failure notification emails to you when your scheduled data auto-refresh succeeds/fails. Knowing your email helps with this too. In order to be able to put Salesforce data into your spreadsheets we need to be able to view and manage your spreadsheets, and to get that data we need to be able to connect to an external service (Salesforce API).
After you give the requested permissions, the add-on will be installed and ready to use