Adobe Launch - help configuring a private key for SFTP hosting

Hi, i am creating my first Launch property that will be using SFTP hosting. 

i have configured my server and port and username but the last requirement is to encrypt private key.  https://developer.adobelaunch.com/api/guides/encrypting_values/

this is my first time and i am looking for step by step instructions on how to do this. 

thanks!

p.