Create a new file deploy.php
in the project root (if it does not already exist)
In this file add the contents below and edit/add the host/s as required
<?php
namespace Deployer;
require 'recipe/mage.php';
host('server.hostname')
->port(22)
->stage('dev')
->user('www-data')
->set('branch', 'develop')
->set('keep_releases', 1)
->set('deploy_path', '/some/deploy/path')