The integration with Google Drive lets you link files from Google Drive directly to projects and cards in Forecast. The files will not be uploaded to Forecast, but it will still show up as an ordinary file - just with a link to the file instead. This means that you can keep your work iterations in Google Drive, and the file in Forecast will always be up-to-date.
When activated you'll see a new button in the files tab on cards, and a similar button in files tab on a project.
Step 1: Go to the Google Drive integration, click here.
Step 2: Click Enable
Step 3: Authorize the integration
You're good to go!