In order to install MySalesData for Salesforce Google Sheets Add-on you have to
- Open any Google Sheets document and navigate to top menu Add-ons -> Get add-ons as on the picture below
- In a a new dialog in a search field type MySalesData and click on a blue "FREE" button and new dialog will appear one by one: the first will propose to confirm Google Sheets account under what you want to install the add-on and the second dialog will appear with the request to confirm API permissions for MySalesData Add-on. You have to press allow for add-on to function properly
- After the add-on is installed the text with the short description will appear under Add-ons menu and you can start working with MySalesData for Salesforce Add-on such as now it will present in the Add-ons menu