Invoking "cmake" failed error

Hi,
I am getting the following error while working on the ROS basics in 5 days C++. Please assist.

CMake Error at exercise_22/CMakeLists.txt:151 (target_link_libraries):
Cannot specify link libraries for target “/opt/ros/noetic/lib/libroscpp.so”
which is not built by this project.

Thanks,
Kshitij Sharma

I was able to remove this error by resetting the workspace. But now I have another issue as shown in the snapshot below:


Please help @duckfrost
Thanks,
Kshitij