I need to know how to make building collapse?

In forge map, I was told that you can make buildings collapse. I need help with that because I cannot do this at all. If there is any help, it would be great because on YouTube after seeing Forge Light’s vids, I wanted to do that for my forge map. How can I do this? Please, I need some assistance and it would be great. Send me a message if you would like to assist me in these parts.