We start by adding CDN Vue 3 on the <head> of our page.
By doing that on dev mode and running our page we have returning on the inspection console this message:
You are running a development build of Vue. Make sure to use the production build (*.prod.js) when deploying for production.
This opportunity we make the 'Vue app construction' over the same page within a <script> embeded tag.
Further ocations we'd be using an external .js file to make all Vue3 interactions.
const app = Vue.createApp();
is the app constructor.
Over an other <script> tag, at the end of our page,
const loadApp = app.mount(#id);
reffers to where we'll print and use the Vue App created on the HTML page.