Load the respective script by adding the following script tag to the head section of your website.
The script will be loaded in a non-blocking way. So you don't need to worry about where to include it exactly.
<script src="https://cdn.jsdelivr.net/npm/add-to-calendar-button@2" async defer></script>
Start using it by adding a <add-to-calendar-button> tag to your HTML source code - with the options as attributes.
Yes, it is that simple.
Your code block could look like the following:
<add-to-calendar-button name="Title" options="'Apple','Google'" location="World Wide Web" startDate="2023-10-23" endDate="2023-10-23" startTime="10:15" endTime="23:30" timeZone="America/Los_Angeles" ></add-to-calendar-button>