I was able to save my edited video from an Android app that I got from the google play store. It saved to in the Download folder built into Chrome. I accessed the 32GB drive by using the "Files" app that the chrome-book has when you buy it. Just go to the apps icon in the tray to see all the apps both Chrome and Android will be there. That is where the "files" app will be.
Later I used the files app to copy my video to my USB thumbdrive...
Hope this helps...