Q:

SSH connection setting through Prompt in iOS

I am trying to set up SSH connection in my iPad through Prompt.  I am following the instructions found here, but I don’t really get the password. 
From my understanding, the password should be the key but not my GCP login password.  I get the key from 
metadata > SSH Keys

but I can’t copy the key to “Paste from Clipboard” and show “Invalid Key on Pasteboard.  The pasteboard does not contain a supported private key.” 
How can I load the key? 
It’s probably kind of stupid question to expert but this is the first time for me to deal with SSH and I have been trying for days already. 
Many thanks. 

A:

If you need to manage your own credentials, use third-party tools, or connect to an instance by using alternative connection paths,
Normally, Compute Engine creates and manages SSH keys for you whenever you connect using the methods described in Connecting to instances
However, if you need to use your own SSH keys (for example, when using third-party tools such as Prompt), you must generate your own SSH key pair and provide your public SSH key file to the instance before you can connect. 
If you're not familiar with how to generate your own SSH key pair and how to locate your public SSH key file, see Creating a new SSH key and Locating an SSH key
You must use SSH keys to SSH to GCP instances, using username and password is only supported with serial connection. 
In particular for Prompt I don't see it listed as a supported connection method in the documentation, although I think it should work, seems you are having problems using the App and not with GCP, maybe this link will help you

