Okay kiddo, let me explain it to you nice and easy. Egypt and Gaza are two places that are right next to each other. But there's a border between them that's like a line drawn on the ground. Nobody is allowed to cross that line without permission. It's kind of like when you have a fence in your backyard and you tell your friends not to come into your yard without asking you first.
The reason why this border is so important is because it separates two different areas. Egypt is a big country that's part of Africa, while Gaza is a small territory that's part of the Middle East. They have different laws, languages, and cultures. The border helps keep things separate and helps the governments of Egypt and Gaza make sure that everything is under control.
But sometimes people try to cross the border without permission, and that can cause a lot of problems. Sometimes people from Gaza might try to go to Egypt to find work or visit family members, but if they don't have the right documents or if they go through unauthorized areas, they could get in trouble. And sometimes people from Egypt might try to cross into Gaza to bring in goods or help their friends and family members who live there, but they could also get in trouble if they don't follow the rules.
So even though the Egypt-Gaza border might seem like just a simple line on a map, it's actually a really important way to keep different areas separated and to make sure that everyone stays safe and follows the rules.