I understand nearly nothing to the functioning of EC2. I created an Amazon Web Service (AWS) account. Then I launched an EC2 instance.
And now I would like to execute a Python code in this instance, and I don't know how to proceed. Is it necessary to load the code somewhere in the instance? Or in Amazon's S3 and to link it to the instance?
Where is there a guide that explain the usages of instance that are possible? I feel like a man before a flying saucer's dashboard without user's guide.
Launch your instance through Amazon's Management Console -> Instance Actions -> Connect 
(More details in the getting started guide)
Launch the Java based SSH CLient
Plugins-> SCFTP File Transfer
Upload your files
run your files in the background (with '&' at the end or use nohup)

Be sure to select an AMI with python included, you can check by typing 'python' in the shell. 
If your app require any unorthodox packages you'll have to install them.
How to run a code in an Amazone's EC2 instance?