I'm learning Vue.js, but I'm just starting out and there are some parts that I can't understand, so please teach me.

Regarding the reuse of components, the part called the content content cannot be displayed at present.
Is there something wrong with the description?

Thank you.

  <my-component title-text = "Title" content-message = "content content"></my-component>
  Vue.component ('my-component', {
    template: `
    props: ['titleText, contentMessage']
  new Vue ({{
    el: "#text",