Okay kiddo, the Scotland Act 1998 is like a special set of rules that tell Scotland how it should govern itself. It's kind of like a book of instructions that tell Scotland what it can and cannot do in certain areas, like education, health, and law-making.
Before this act, Scotland didn't have much say in how things were done in their own country. But with this new set of rules, they were able to make their own decisions about certain things that affect their daily lives. For example, they can make laws about how their schools are run, how their hospitals are funded, and how they want to protect their environment.
The act also created a special group called the Scottish Parliament, which is kind of like a team of people that represent Scotland and make decisions for the country. Before this act, Scotland didn't have its own Parliament, so this was a big deal.
Overall, the Scotland Act 1998 was a way to give Scotland more control over its own affairs and to give its people a stronger voice in how their country is run.