The calendar will be added on the left side under "Other calendars".
Confirm that the subscription is working by verifying that events are appearing in the calendar grid.
Configure your Android device to sync to your Google calendar.
Go to your device's Calendar app.
In the settings, make sure your Google account is checked, then select 'Sync Now'.
You may need to select the Google account calendar, then under "Other calendars" check the subscribed calendars the Android device is to sync with (by default, the "Other calendars" may not be checked).
In newer versions of Calendar (Android 5.1 and above), Refresh calendars by clicking the ⋮ icon (top roght) and then on 'Refresh'.
Now click on the Menu icon (top left), scroll down and click on 'Settings'.