This video shows you how to use a bike chain breaker. A bicycle chainbreaker is a tool for breaking the links of a bike chain so you can remove or install a new bike chain. Using a bicycle chain. Breaker is very simple. In this video, I show you how to use a bicycle chain breaker to break a bicycle chain. If you are installing or removing a bicycle chain, this is how to break the chain apart, and also how to put it back together. A chain breaker is used for cycle chain fitting. A bike chain breaker has a screw down pin that you used by turning a handle to push the pins out of the bicycle chain links. When you are pushing the pin out of a bike chain link, make sure you don’t push it all the way out, and leave it stuck in the chain so that you can easily push it back in to reinstall the chain. 
Here’s where you can buy the park tools mini bike chain breaker.
https://amzn.to/3Me1C8j