how to append child in js code example

Example 1: appendchild javascript

const parent = document.createElement('div');
const child = document.createElement('p');
const childTwo = document.createElement('p');
parent.append(child, childTwo, 'Hello world'); // Works fine
parent.appendChild(child, childTwo, 'Hello world');
// Works fine, but adds the first element and ignores the rest

Example 2: how to appendChild in the begin of the div javascript

var element = document.getElementById("div1");
element.insertBefore(para, element.firstChild);