How to build docker images using a Declarative Jenkinsfile

I'm new to using Jenkins....

I'm trying to automate the production of an image (to be stashed in a repo) using a declarative Jenkinsfile. I find the documentation to be confusing (at best). Simply put, how can I convert the following scripted example (from the docs)

node {
    checkout scm
    def customImage = docker.build("my-image:${env.BUILD_ID}")
    customImage.push()
}

to a declarative Jenkinsfile....

You can use scripted pipeline blocks in a declarative pipeline as a workaround

pipeline {
    agent any
    stages {
        stage('Build image') {
            steps {
                echo 'Starting to build docker image'

                script {
                    def customImage = docker.build("my-image:${env.BUILD_ID}")
                    customImage.push()
                }
            }
        }
    }
}