Merge google and outlook calendar

Are use Google calendar for personal and a side hustle, and I use outlook for business. I am using look like a boss so that people can schedule appointments with me. But I need them to see the combination of both of the calendars to show all of my books time so they only choose from what is legitimately free time.

I found a YouTube video showing me how to get the URL of my Outlook calendar and add to my Google calendar so it would show booked time but that has not appeared to work so far.

What do I need to do to achieve the end result?

Are you able to share the link to that video?