Egyptology is the study of ancient Egypt. Imagine if you found an old writing paper from your great-great-great-grandfather from a long time ago. That paper had old stories or writings about his life and the things he did.
Egyptologists find old stuff (like papers, buildings, and monuments) from ancient Egypt. They study these things to learn about the people and their lives a long time ago. They read the stories written by the people, they look at pictures on the walls and they study the buildings to try to understand how the people lived and what they believed. They even look at the tools and artifacts (artificial objects) they used, like pottery, statues, and jewelry to learn about their culture.
Sometimes they discover things that nobody has ever seen before, like the tomb of Tutankhamun, and these discoveries help to tell us more about ancient Egypt. It's like being a detective and piecing together clues to understand what life was like a long, long time ago in ancient Egypt.