Looking for examples of an in-game tournament system

Hello! I am working on a CCG and want to implement an in-game tournament system. I was looking around the internet to find out how people usually implement these kind of things but couldn’t find much. I would kindly appreciate some links to videos, blogs or preferably store assets (doesn’t matter free or not) so that I could have an example of where to start. Best I could find is this:…LD9QdY5SeZoi9g but this runs on version 4.19 and my project is on 4.21 sadly. So thanks in advance for any resources!