Help w/ SSH Config

I have a client who gave me the host name, port, remote directory, user name and their SSH public key. I am running WinSCP 5.15.2 and the setup I am using keeps asking me for a password. I am having trouble figuring out how to set up the site so that it will use the SSH key and not require a password. I am a bit new at this, so I am sorry if this is in the documentation somewhere - I couldn't find it.

Then it does not look like they gave you all credentials.
You either need a password or a private key.