Once enabled you get a second option for adding files.
When clicking the Google Drive icon for the first time when uploading files you will be taken to a Google Log in page where you connect your Favro account with a Google Account of your choice.
Note: Even if you signed up using Google authentication you will need to connect your Favro account for the integration as well.
Once logged in to your Google account you can search for and select any file you want to attach.
Adding files from your Google Drive creates a link between the card in Favro and the file in your drive.
Clicking the file will open a read-only preview of the file within Favro and clicking Open in Google Drive will open the file in a separate tab.
You can use the sharable link to the document you want to upload. After the link is copied to your clipboard just open the card in Favro where you like to attach the document and hit PASTE.