Add custom Bootstrap 4 html and library to Project

I am trying to add this Bootstrap 4 html and javascript to my project. how to i add custom CSS and javascript and then use it in my project. I have try many things nothing seems to work. Below is the html code and javascript below.

============== HTML =======
link rel="stylesheet" href="">
script src=""></script>
div class="card-body">
    div class="wrapper text-center">
        h4 class="card-title">Alerts Popups</h4>
        p class="card-description">A success message!</p> 
button class="btn btn-outline-success" onclick="showSwal('success-message')">Click here! /button>
============ Javascript ====
(function($) {
showSwal = function(type) {
'use strict';
if (type === 'success-message') {
title: 'Congratulations!',
text: 'You entered the correct answer',
type: 'success',
button: {
text: "Continue",
value: true,
visible: true,
className: "btn btn-primary"

swal("Error occured !");


You need to add your stylesheet and script src in “Properties > extraheaders”

<link rel="stylesheet" type="text/css" href="">
<script type="text/javascript" charset="utf8" src=""></script>

@seetheo - Tip : If you’re pasting code, html or config files, surround the code with triple back ticks (```), before the first line and after the last one. It will be formatted properly. (We fixed it for you this time)