There are essentially two ways to update the application. Automatically or manually.
Automatic updates: Whenever a new version is available, the application will download it in the background. Once the update is ready, you'll see a notification bar on the top of the application, telling you that there is an update available. Once you click on the download button in the notification bar, the application will start updating itself.
Manual updates: Using the RaceLab webpage and clicking on the download button: LINK