Once you do that sign in and select the device ‘WindowsPhone’ that should be displayed (I’m using HTX Windows Phone 8S). Now you should be able to customise certain things like what calendars are displayed, enabling ”delete mail as trash’ for this device’ for example. Once your done save and sign out. Now the next problem you’ll encounter is that you do not immediately see the synced calendars as part of your phone calendar. Go to settings for your phone not you calendar, just the general settings for the phone. Go to ‘email+accounts’ and select your google account. Scroll down and deselect ‘calendar’ from the content you want to sync. Then save. The reason you do this is to force sync the calendar; once you save you’ll notice the google account is greyed out as it’s ‘synchronising’. Once its done reselect your google account and reselect ‘calendar’ under content settings. Save and voila :). It should grey out again because it’s synchronising; then go back to your calendar and check under the calendar settings that your multiple google calendars are there. Hope this helps! Good luck :D!