Foreground layers are combinations of tiles meant to be drawn on top of your player, not behind them. Almost everything we've built so far has been a background layer as our player is meant to walk on top of the various tiles we've placed on our map. However, there are a few sections in which our player should be able to walk "behind," such as the tops of houses and trees.

This video will help you understand why we have to create a separate layer for foreground objects and how to do so within Tiled.