Maybe this is a silly question, I just set up free Amazon Linux instance according to the tutorial, what I want to do is simply running python scripts.
Then I googled AWS and Python, Amazon mentioned Boto.
I don't know why using Boto. Because if I type python, it already installed.
What I want to do is run a script on day time. 
Is there a need for me to reading about Boto or just run xx.py on AWS ?
Any help is appreciated.
Boto is a Python wrapper for AWS APIs. If you want to interact with AWS using its published APIs, you need boto/boto3 library installed. Boto will not be supported for long. So if you are starting to use Boto, use Boto3 which is much simpler than Boto.
Boto3 supports (almost) all AWS services.
Running Python scripts on Amazon Web Services? Do I need to use Boto?