How to rotate bone or object with invers kinematic and constraint child of?

youtube.com/watch

So i have this project where I am able to drag or move an end effector freely and the arm will rotate (just like in the video). But when i try to rotate the arm, it won’t work. The end effector nor the arm are rotating or moving. I need to rotate this arm so I can use it for scripting with Python. Please help :')