How do you find your GitLab hostname (to verify your SSH key)?

I just created a personal GitLab account and am trying to follow the steps on

https://gitlab.com/help/ssh/README

to deploy my SSH key to GitLab. I followed up to step 5 and will see my SSH key among "your SSH keys" in my user settings -> SSH:

I am trying to complete an additional sixth step by checking the key:

My username is GitLab khpeek

, so I guessed that my GitLab domain is gitlab.com/khpeek

. However, the check command

ssh -T git@gitlab.com/khpeek

      

        
        
        
      

    

an error message is displayed:

ssh: Could not resolve hostname gitlab.com/khpeek: Name or service not known

      

        
        
        
      

    

This appears to be the wrong hostname. What would be right?