scp introduced during ssh keygen without explanation

[monica-georgia]

hi there,

As a contribution for checkout i reviewed the first portion of this lesson. I thought it was really well formatted and constructed. In my expereince in the genomics world however: using scp during set up to transfer private keys causes confusion because it's often the first time it's used. You've done an excellent job of explaining this later on in the lesson https://carpentries-incubator.github.io/hpc-intro/15-transferring-files/index.html#transferring-single-files-and-folders-with-scp, but when it's first mentioned there is a definition only https://carpentries-incubator.github.io/hpc-intro/11-connecting/index.html#transfer-your-public-key . I suggest perhaps either adding a link to the "transferring files" explanation, or adding a few lines of text to explain how the 'scp sshkeylocation location2:path' command works.