I am struggling to add Customer Insights Journeys data (such as marketing activities; email opens, clicks etc.) to Customer Insights Data. I have already made the connection between both applications, but I'm not sure what to do with it and how to pull the rest of the marketing data into CI Data. I have already tried creating marketing activities on contacts, but I'm a bit lost on which fields to include.. The Learn documentation is very limited on this subject, is there someone who can help me to get started?