At this time you can only import an iCal feed into the global diary.
To import an iCal feed into CampaignAmp:
Head to the global diary
Select "Add Information" and then "iCal Import".
Copy the iCal URL from your Google or Apple Calendar and paste into the relevant box
Your iCal information will then appear in CampaignAmp - you will then need to associate the events with each campaign & dashboard
NOTE: If you make any changes in iCal, you'll have to re-import the calendar to see your changes in Campaignamp.