If only Chapter 1 is showing available, then you'll need to download and install the patch that contains Chapters 2 and 3.
Start up the game as usual (make sure you are connected to the internet), and the first game screen that you see will tell you if there is a patch available. Click on the notification to start download.
If there's no notification -- then uninstall and reinstall the game. (There was a problem with the patch for Chapter 3, and many of us had to use this workaround.)
Let us know if you still have problems.