Export your calender in the management console, the link will look like
https://www.kampi.co.za/export-calendar?id=95 where the 95 will be your campers ID. Once you have this URL you can add this as a web calender in Google Calender as per below.
Instructions from support.google.com
Use a link to add a public calendar
Important: You can only add a calendar using a link if the other person's calendar is public. Learn more about public calendars.
On your computer, open Google Calendar.
On the left, next to "Other calendars," click Add Add other calendars and then From URL.
Enter the calendar's address.
Click Add calendar. The calendar appears on the left, under "Other calendars."
Tip: It might take up to 12 hours for changes to show in your Google Calendar.