SSH with putty and SFTP

if the keypair is in PEM extension, open PuTTY Gen and load the PEM file, then press 'save private key' to save the 
private key as a PPK file. 

# SSH with Putty:

In Session, add the Host name and the port.

In Connection > SSH > Auth, add the PPK file in the 'Private key file for authentication' box.

In Connection > Data, add the user for the ssh connection(auto-login username).

# SFTP:

Open a connection, choose the host and port(usually port 22). 
Set the Logon type to 'key file' then set the file and the user.
Connect.