In interest of helping anyone else with this in the future, who is new and can't figure it out:
Creating a KeyPair with the "Access & Security" panel, and then using that pair in the "Quick Launch" panel, does not work.
They way to do this:
When you create an SSH key pair via the "Access & Security" panel you are prompted to download the key. Do so.
Open it in PuTTYkeygen (downloadable tool). In PuTTYkeygen, add your own comment and passphrase (akin to a prompt and password, respectively), and save a private key.
THEN, create the instance of your server in the "Quick Launch" panel.
When prompted for an SSH key at the bottom, add a new one! DO NOT use the one generated in the "Access & Security" feature.
Here, copy and paste the public SSH key displayed in PuTTYkeygen.
You can follow the rest of the instructions located here:
I thought the SSH key created on the site, could be used on the site. That seems reasonable to me, someone who doesn't know about that kind of thing, but it's wrong. And at least now, anyone else equally uninformed will know.
/edit: Oh! Thanks for the response smaffulli. I had this open from this morning checking to see if anyone had responded yet. I didn't refresh before posting this.