Thanks, well Artie interesting, a lot of this is hard to follow..

"then launch the file "Install OS X El Capitan", and proceed as above".

What I"m asking is how does one launch a file from one hardrive onto another hardrive?

That's why I'm not sure the having the install El Capitan will work. You have a erased Mac HD that has no structure. How do you launch the OS onto it?

I just erased my old Mac HD, the old 27" I'm going to see. One of the instructions was to be on the wifi, which is in menu upper right. I think I was in recovery mode.

I'm only on SD now. I worry a bit about it not having that recovery drive, which is not a life and death thing, but it's a nice tool to have.