Open your Google Calendar within a web browser.
Click on the Other Calendars dropdown menu link (to the right of Other Calendars)
Select "Add By URL" to get the following screen.
Insertas your personalised address.
Optionally, to make this google calendar available to other platforms, like a BlackBerry 10, you should tick the box to say "Make publically accessible?" as in the following screen shot.
Then click Add calendar and you are complete.