how to convert this jenkinsfile to scripted pipeline

i have jenkinsfile code like this, i trying to convert this to scripted pipeline all night but keep error, can you help me please, thank.

pipeline {
agent {
    docker {
        image 'maven:3-alpine'
        args '-v /root/.m2:/root/.m2'
    }
}
options {
    skipStagesAfterUnstable()
}
stages {
    stage('Build') {
        steps {
            sh 'mvn -B -DskipTests clean package'
        }
    }
    stage('Test') {
        steps {
            sh 'mvn test -Dmaven.test.failure.ignore=true'
        }
        post {
            success {
                junit 'target/surefire-reports/*.xml'
            }
        }
    }
    stage('Deliver') {
        steps {
            sh './jenkins/scripts/deliver.sh'
        }
    }
}

}