The kayaking program runs parallel to the regular program. When the non-kayakers go for a landing or Zodiac cruise, the kayakers go kayaking. This means you can always join the regular program.
The kayaking is done near the landing sites of the regular program. These sites are mentioned in your itinerary. As the itineraries are different for each trip, you have to look at your program to find roughly the area where kayaking will be done.