Check out example codes for "fontawesome cdn". It will help you in understanding the concepts better.
Code Example 1
<link href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/5.13.0/css/all.min.css" rel="stylesheet">
Code Example 2
Make sure to put this just before the </body> tag!
<script src="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/5.13.0/js/all.min.js"></script>
Code Example 3
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css" integrity="sha384-wvfXpqpZZVQGK6TAh5PVlGOfQNHSoD2xbE+QkPxCAFlNEevoEH3Sl0sibVcOQVnN" crossorigin="anonymous">
Code Example 4
<link rel="stylesheet" href="path/to/font-awesome/css/font-awesome.min.css">
Code Example 5
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css" crossorigin="anonymous">
Code Example 6
<link rel="stylesheet" href="https://pro.fontawesome.com/releases/v5.10.0/css/all.css" integrity="sha384-AYmEC3Yw5cVb3ZcuHtOA93w35dYTsvhLPVnYs9eStHfGJvOvKxVfELGroGkvsg+p" crossorigin="anonymous"/>
Code Example 7
<link rel="stylesheet" href="path/to/font-awesome/css/font-awesome.min.css">
Code Example 8
gem 'font-awesome-sass'
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