[Tutor] A basic question

[sharon]

I have been trying how to get a any python program to run by clicking on 
the icon.  I keep reading on the internet  make it executable:

chmod a+x try_python.py

Where do I actually put the above expression so that it will work 
everytime.  If I then sent this try_python.py  to someone else with 
Ubuntu would it run on their system?  Sorry if this is too basic but it 
is an assumption that seems to be made and I really am a complete beginner.

Thanks for any help

Sharon