Login to AWS EC2 via Windows 10 OpenSSH, without Putty
Describes how to login to AWS EC2 using Windows 10 OpenSSH, without Putty. With this, you don't need to convert your .pem private key file into the .ppk format. You can straightaway download your .pem file from AWS EC2, and use it via Windows 10 SSH to login to EC2.
However, you do need to install OpenSSH client on Windows 10. This video guides you through the OpenSSH installation as well.