Struggling with Implementing an iframe on my website

Hey Guys! I’m trying to add an iframe onto a website. I’m not really good with front end code and so the directions are a bit confusing. I’ve included the directions below. Any help on this would really be appreciated.

Thanks,
Conner

DIRECTIONS

Warning: DO NOT load the iFrame directly from the on load event of your website.
Failure to follow these instructions will result in severe reporting inaccuracies.

The patient clicks a button or link on your website and Online Booking appears via an iframe.
1. Place a link on your website the patient can click.
2. Using the click event, create a NEW iFrame element.
3. Set the src attribute of the iFrame to the URL provided.
4. Add the newly created iFrame element to your website

Example:

Put a button or link on your page and a container to put the online booking iframe:
Book an appointment!

Create the handler to that button or link to create the iFrame and show it:
var showOnlineBooking = function() {
var iframe = document.createElement(“iframe”);

    iframe.src = 'https://...';  //use the url from the "Book on your website" button located on Settings->Schedule Template
    document.body.querySelector("#olb").append(iframe);
};

Suggested widths and heights:
Mobile: max-width: 480px; height: {any value to fit design}
Desktop: min-width: 600px; height: {any value to fit design}