Which course and app you are asking about isn't clear to us. If you want to lean about the psychology then you can follow the resources as mentioned below:

• MIT Open Course ware
• Stanford University Open Courseware
• NPTEL SWAYAM

This resources have courses for free from top notch psychologist and Psychological researchers all over the world.

I would recommend you to repost the question with the name of the app so that we can understand and can guide you out.

To know more about Psychology visit the link below:

https://www.careers360.com/courses/psychology-course

I hope this answer helps. All the very best for your future endeavors!