To add an SSH key to your shells account please do the following:
1. In your account select SSH Keys on the left side.
2. Select Create on the top right.
3. Give your SSH Keys a name where it says Label* then click create
Once you have added a label, select the label (If you only have one, it will be select for you) and click on create. Here is where you can paste your key if you have generated one on your remote host. It will only save if the key is pasted incorrectly. The SSH keys will be added when you reinstall and select your SSH key chain that you have created.
SSH keys can be verified by opening a terminal on Ubuntu and inputting the following:
"~shellsuser" would be replaced with your actual Ubuntu username