How to run gr-howto Python or C++ files from ubuntu

Hi, I am new in this platform and trying to run my first block in Gnu Radio. Using tutorial script from OOT modules,  I am unable to run C++ or Python files (e.g. qa_square_ff.py) from cmd window.

 

When I use "python3 qa_square_ff.py" command, it always says some module (e.g. howto_swig) is missing.

Is there any step by step guideline to run this type file from cmd window?

Regards,

Rupak