@hnahli that has nothing to do with what you are trying to do. After you install and activate the plugin nodebb-plugin-emailer-mailjet you will see an option for Mailjet under ACP -> Plugins menu. You will find instructions there.
@frissdiegurke it is working now I just had to validate my domain with mailjet. The Nodebb installed and running on 0.0.0.0:4567 but the confirmation link sent without specifying the port #. How do i fix that?