Describe when someone would need this information. For example "when connecting to wi-fi for the first time".

Step-by-step guide

Pre-requisite: In the ssh config file write the below 

Host ela

    HostName ela.cscs.ch

    User <username>

    IdentityFile ~/.ssh/cscs-key

Host daint-ela

    Hostname daint.cscs.ch

    User <username>

    IdentityFile ~/.ssh/cscs-key

    ProxyJump ela

Host eiger-ela

    Hostname eiger.cscs.ch

    User <username>

    IdentityFile ~/.ssh/cscs-key

    ProxyJump ela

Note:

1. The ssh config file can be written in many different ways, the above sample is for your reference only
2. username in the above snippet needs to be configured with your cscs username
3. The naming convention for Host is given as daint-ela or eiger-ela as an example and it's your own preference

Step - 1: Users either need to log in to the SSHService web application to generate keys and download (or) Users may download the keys using the sshservice-cli 

Step - 2: Make sure the downloaded keys are copied to ~/.ssh with names cscs-key & cscs-key-cert.pub (also permission on cscs-key should be set as 600) 
(The above two steps are required if you are connecting for the first time or if the downloaded keys got expired)

Step - 3: Connect to eiger or daint with the command below, 

                ssh daint-ela 

                or 
                ssh eiger-ela