setting pythonpath variable in environment variables

[saisankalpj]

parent/
    __init__.py
    one/
        __init__.py
        sample1.py
    two/
        __init__.py
        sample.py
  

I have a structure like above.The code works fine in PYCHARM IDE.To run the program through command prompt,I have set environment variables like PYTHON_HOME,PATH variables.Now when i run the code througb command prompt,it doesnt run like
<c:/users/parent>python two\sample.py.The error which i get is like "No module named one",as sample.py file has an import like "from one.sample1 import *" But when i set PYTHONPATH variable and run the code same way it runs.
PYTHONPATH is set as c:/users/parent
How can i understand this.?Is it correct way to run the code through command prompt?.Please help me to understand this