All games that you make in GameMaker Studio 2 need at least one room to run (but can have many, many more) , and a room is just a space where you place instances of the objects that make up your game as well as tiles and any other graphical resources. When you first create a room in your resource tree you will be presented with a new window with which to edit its properties, something like this:

By default the room tools will be placed on the left, with three main sections:

• Layer Editor: Everything in a room is placed on layers, and there are different layer types that you can choose from (more on this later). Layers are ordered by depth and this depth is what defines the order in which the layer contents will be rendered to the screen when the game runs. Depth ordering is from highest to lowest, so that the lower the depth the nearer the "camera" and the higher the depth the further away. For example, a layer with a depth of -300 will render over a layer with a depth of -100, and a layer with a depth of 1000 will render under everything with a depth less than this.
  
  
• Layer Properties: Each layer that you add to the room will have its own properties, and those properties will change depending on the layer type. This window permits you to change those properties and edit how the layer will be rendered.
  
  
• Room Properties: Rooms have a number of properties too, and these can be set here. Things like the room size, the camera view ports that are active and a few other things can be set here.
  
  

We've mentioned that there are different layer types, so let's just go over what they are and how they can be used when building your games:

	Background Layer	The background layer is a layer that can be filled with a single colour or a single image. It can be moved and positioned within the room, and you can have multiple background layers. Generally this is used, as the name suggests, to generate a constant background fo rall the other layers in the room. By Default a new room will always contain a background layer, but you can remove it if you don't need it.
	Instance Layer	The instance layer is where you place all the instances of the objects that you require for the game. To add an instance to a layer, simply click on the object in the resource tree and then drag it into the room editor workspace. When you release the mouse button, an instance of that object will have been added to the room. By Default a new room will always contain an instance layer, but you can remove it if you don't need it.
	Tilemap Layer	After having created a tile set, you need to add the tiles to your room, which is done by creating a tilemap layer. A tilemap layer is a layer that permits you to add tiles from any of the tile set resources that you have created and will be set up automatically to use a grid the size of the tile set cells. You can only add a single tile to each grid cell, so if you require multiple tiles to occupy the same space, then you should be using multiple tilemap layers.
	Path Layer	The path layer is the only one that does not actually get rendered when you run your game. This layer is more of a "convenience" layer for helping you to create or edit Path resources, since it permits you to add or edit paths within the actual room space.
	Asset Layer	Sometimes you want a nice graphical effect but don't want the overhead of using an instance or don't need it to do anything other than draw itself. You could use a tilemap, but given that tilemaps are restricted to using a grid and only a single image per grid cell, they can be a bit restrictive. This is when you would use the asset layer. The asset layer simply takes a sprite resource and draws it using the paramters that you set when you add it into the room. Sprites can be added to this layer the same way that instances of objects are added to the instance layer, ie: you click on the sprite in the resource tree and then drag it into the room editor workspace.