Backup Configuration with Key Authentication?

Hi all, Previously, I had set up a backup configuration using: SFTP to my Mac w/ Sierra using password authentication. This works fine. But Now I want to switch over to using key authentication instead. I am not sure how to set this up from WHM and going to MAC sierra. I believe that I know how to set up keys on my Mac Sierra, however - I don't know how to set WHM up correctly. Can anybody provide some assistance? Thanks in advance " Dave