Facebook Pixel - How to add checkout event?

Hello there,

I have some questions about Facebook Pixel that I’d like to ask.

I have installed Facebook Pixel on my website, which currently tracks three basic events:

Viewed product
Added product to cart
Purchased product

However, I would like to include the fourth event, which is ‘Checkout page’ It seems like crucial information for optimizing my campaigns. Could you please guide me on how to add this event to my pixel tracking?

Thank you so much for your assistance.

Best regards,

Here is my site Read-Only: LINK
(how to share your site Read-Only link)