I have followed all the prcedures twice and cannot find the my_package under src
Which course is this?
Also, ensure you have created the package in the right directory:
cd ~/catkin_ws/src ...
If you still have problems, please share a screenshot so we can see what you are seeing.
It is the ROS2 with c++ course. This problem arises in chapter 2.5.
Please address the points I raised earlier (here), so we can know how to help you.