Log in to SSH Authman. You are required to use Duo 2FA to access SSH Authman. Once you have logged in, you will be presented with a screen like this:
Click the Add Key button and paste your SSH public key into the form. Do not paste your private key. Next, fill in the description. The description must be unique and is to help identify your keys in the future.
Once you have added your key, you will be redirected back to the list:
Deleting a key from SSH Authman
If you suspect that your SSH private key has been compromised, or you have lost the device for that SSH Key, you can remove the old key by going to SSH Authman and deleting the appropriate key. You will be asked to confirm the deletion of the key.