Instant crash

[Alejandro-Moreno-Alonso]

Maybe i'm doing something wrong, but i followed each and every step, checked that my git account is fine (email and user) and when i click to open it with python, it instantly closes the window.

[4ig]

and when i click to open it with python

This is not the way it is supposed to be done. Please check the second step of the instruction:

Download the contribute.py script and execute it passing the link on the created repository
python contribute.py --repository=git@github.com:user/repo.git

This means you need to open Terminal if you are on Linux or Mac or Command Line if you are on Windows and execute it from there.