Okay kiddo, do you know what a country is? It's like a really big family of people who all live in the same place and follow the same rules. And just like how you might have a special song you sing in your family, a country also has a special song called an anthem.
The Republic of China is a country that is also known as Taiwan. They have a special flag that represents their country and they also have an anthem that represents their country too. The anthem is called "Zhōnghuá Mínguó gúogē" which means "National Anthem of the Republic of China".
When people from Taiwan hear this song, they know it's time to show respect for their country. They might stand up and put their hand over their heart or even sing along. It's a way to show that they are proud to be from Taiwan and they love their country.
So that's what the national flag anthem of the Republic of China is all about - it's a special song that represents a country called Taiwan and reminds people to be proud of where they come from!