When you return to your Drive after authorizing offline access, you'll see a notification box in the upper left, indicating that your files are being synced offline. While you have an Internet connection and are signed into your Google account, your most recently opened documents, spreadsheets, and presentations will sync and be available for offline viewing when you open Chrome.
To sync documents, spreadsheets, and presentations, you must have an Internet connection. To view sync progress, click the gear icon 
in the upper right of your browser window. You'll see a grey status message indicating sync progress or the time when your Drive was last synced.
You can view all of the items you have available offline by selecting the View offline Docs menu item. You can also disable offline access by selecting Stop using Docs offline. Disabling offline will also remove the offline copies of documents, spreadsheets, and presentations stored on this computer.