3th of 3 Questions.
How to connect to an EC2 instance using PuTTY for Windows older than 10
Connecting via PuTTY
PuTTY does not natively support the .pem format used by AWS. You must use PuTTYgen to convert your .pem file into a .ppk file before initiating the connection.
Steps to Connect
Open PuTTYgen and click 'Load' to select your .pem file.
Click 'Save private key' to generate and save the .ppk file.
Open PuTTY and navigate to Connection > SSH > Auth > Credentials.
Browse for your .ppk file in the 'Private key file for authentication' field.
Return to Session, enter the instance public IP, and click 'Open'.