Hi na yang,
Guess you missed the association with Course and Training,
In the microflow ACT_Course_ScheduleTrainingEvent a new TrainingEvent object is created with a reference to the Course object. Association is Mendix are defined using the Object ID's which are created and maintained by the Mendix runtime. You won't create your own foreign keys. Which need to be explicitly set when setting the association between two objects. Thus simply referring to an object is sufficient to set the association, because Mendix will pick the object ID automatically.
Please go through the instruction once again,
https://academy.mendix.com/link/paths/31/Become-a-Rapid-Developer
Thanks & Regards,
Manikandan K
In the Course_Overview screen, there will be a List view displaying Courses. Inside the List view, there will be two columns. The first column will show the Course data, and the second column will contain a Schedule button.
For the button, you need to configure a Microflow that:
Once you test it, everything should work as expected.