Imagine you have a bunch of little square tiles in front of you. Each tile has a different picture on it - some have grass, some have water, some have trees, and so on.
Now, let's say you want to create a world for a video game. Instead of drawing every little detail of the world from scratch, you can use these tiles! You place them next to each other like a puzzle, making sure that they fit together just right.
As you add more and more tiles, you start to create a big picture - a whole world that the player can explore. You might add in little characters, buildings, and other things on top of the tiles to make the world even more interesting.
When the player moves around in the game, they move from tile to tile, just like if they were walking on a real-life path. This is how you create a tile-based video game!