1. Select your instance in the EC2 Dashboard and click on connect option.
2. AWS will ask you if you want to generate a Key Pair. If you havent do it and save it.
3. Download Putty Generator and convert your Key Pair file (.pem extension) to PPK using it.
4. Open your Putty. Enter Host ID, User Id.
5. FInally Open the PPK file using SSh Authorization and you should be good to go