Adding CSS and JS to my theme

Hello,

I created a template in which I am using a UI kit from Creative Tim. Now I am trying to turn this template into a Drupal theme, but I am having trouble with getting all the JS to work. I am getting the following errors in my console: https://imgur.com/7XFfOcC

Below is a structure of the CSS and JS files from my template, and then how I am including them in my theme.

In my head (CSS files):

  <!--     Fonts and icons     -->
  <link rel="stylesheet" type="text/css" href="https://fonts.googleapis.com/css?family=Lato:300,400,500,600,700,800,900|Material+Icons" />
  <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/font-awesome/latest/css/font-awesome.min.css">
  <!-- CSS Files -->
  <link href="./assets/css/material-kit.css?v=2.1.1" rel="stylesheet" />
  <!-- Slick Slider CSS -->
  <link href="./assets/css/slick.css" rel="stylesheet" />
  <link href="./assets/css/slick-theme.css" rel="stylesheet" />
  <!-- Custom CSS -->
  <link href="./assets/css/custom.css" rel="stylesheet" />

In my footer (JS files):

  <!--   Core JS Files   -->
  <script src="./assets/js/core/jquery.min.js" type="text/javascript"></script>
  <script src="./assets/js/core/popper.min.js" type="text/javascript"></script>
  <script src="./assets/js/core/bootstrap-material-design.min.js" type="text/javascript"></script>
  <script src="./assets/js/plugins/moment.min.js"></script>
  <!--	Plugin for the Datepicker, full documentation here: https://github.com/Eonasdan/bootstrap-datetimepicker -->
  <script src="./assets/js/plugins/bootstrap-datetimepicker.js" type="text/javascript"></script>
  <!--  Plugin for the Sliders, full documentation here: http://refreshless.com/nouislider/ -->
  <script src="./assets/js/plugins/nouislider.min.js" type="text/javascript"></script>
  <!--  Google Maps Plugin    -->
  <script src="https://maps.googleapis.com/maps/api/js?key=YOUR_KEY_HERE"></script>
  <!--	Plugin for Tags, full documentation here: https://github.com/bootstrap-tagsinput/bootstrap-tagsinputs  -->
  <script src="./assets/js/plugins/bootstrap-tagsinput.js"></script>
  <!--	Plugin for Select, full documentation here: http://silviomoreto.github.io/bootstrap-select -->
  <script src="./assets/js/plugins/bootstrap-selectpicker.js" type="text/javascript"></script>
  <!--	Plugin for Fileupload, full documentation here: http://www.jasny.net/bootstrap/javascript/#fileinput -->
  <script src="./assets/js/plugins/jasny-bootstrap.min.js" type="text/javascript"></script>
  <!--	Plugin for Small Gallery in Product Page -->
  <script src="./assets/js/plugins/jquery.flexisel.js" type="text/javascript"></script>
  <!-- Place this tag in your head or just before your close body tag. -->
  <script async defer src="https://buttons.github.io/buttons.js"></script>
  <!-- Control Center for Material Kit: parallax effects, scripts for the example pages etc -->
  <script src="./assets/js/material-kit.js?v=2.1.1" type="text/javascript"></script>
  <!-- Slick Slider JS -->
  <script src="./assets/js/slick.min.js" type="text/javascript"></script>

In my drupal theme, theme.libraries.yml:

global-styling:
    css:
      theme:
        css/material-kit.min.css: {}
        css/slick.css: {}
        css/slick-theme.css: {}
        css/custom.css: {}
    js: 
      js/core/jquery.min.js: {}
      js/core/popper.min.js: {}
      js/core/bootstrap-material-design.min.js: {}
      js/plugins/moment.min.js: {}
      js/custom-scroll.js: {}
      js/material-kit.min.js: {}
      js/slick.min.js: {}
      js/smooth-scroll.min.js: {}
      js/custom.js: {}
    dependencies:
      - core/jquery

theme.info.yml:

name: "Verdamigo"
description: "Verdamigo template"
type: theme
core: 8.x
base theme: classy

libraries:
  - verdamigo/global-styling

regions:
  primary_menu: 'Primary menu'
  header: 'Header'
  sidebar_first: 'Sidebar first'
  content: 'Content'
  footer: 'Footer'

I guess maybe my problem has to do with the core drupal javascript files not being loaded, or loaded too early or too late?

Thanks in advance,

Mike