How to use regex in Power Automate Cloud flows

I had a client scenario, where I needed to grab a 6-digit number from an incoming email subject. It wont always be in the same place, and also possibly not be the only digits. So I couldnt use trim, length or other that I could think off. Unfortunately, or luckily, depending on how you look at it, my dear friend Cat Schneider introduced me to regex Thankfully someone within my company helped me guide a regex expression I could use, but I do want to share this awesome resource: