BuddyPress.org

Hi,
I’m new to BuddyPress and it’s possible I miss something obvious but I can’t find information about this which is why I hope someone could help me in the right direction or with examples.

I’ve created a Custom Post Type registered to generate activity. And it works.
What I want to do next is, when a user clicks on a specific activity item to get the CPT details (meta fields). But I can’t find the post_id in or any other relation to the post object in the activity data. How can I set up the custom post type or the activity to get post_id be part of the activity?

Any ideas?