The top bar of the panel shows information about your game. The first item is a text field with the game's name. This field is editable. The second item is the game's id, which is unique for every ROBLOX game. Neither of these items are displayed publicly, they are there mainly to help you organize your work.
Inside the game explorer panel are several lists. The first list shows all of the Places that are in your game. You can think about Places as levels or stages of your game. ROBLOX provides services to easily move players between Places. While a game can be made up of many places, each will have one Starting place. This is the first Place players will join if they launch your game. The starting place in your game is indicated by the spawn icon: . Right clicking on a Place in this list allows you to change which Place is the Start Place.
Right clicking on Places and selecting "Add Empty Places" adds a new place to your game. This place will be empty and will only consist of a baseplate (the same as Selecting File > New). Selecting this option automatically creates the place and adds it to the list.
Right clicking on Places and selecting "Change Place List" opens a web window in Studio and navigates to the game configuration page on ROBLOX. This page shares much of the same functionality as the Game Explorer Panel in Studio. The main difference is that the web page allows you to Enable Studio Access to API Services, as well as see any places created by the Create and Save Place API.
Inside of Places in the Explorer are all of the places in your Game. Double clicking on any of the places will automatically open that place in a new instance of Studio. Right clicking on a Place allows you to change the Places's name, set the Place as the Start Place of the game, or remove the place from the game.
For more information on how Games and Places are organized, see Games and Places.
The second section in the Game Explorer is for Developer Products. Developer Products are the service you can use to charge players Robux in your game. Right clicking on Developer Products allows you to configure the Products that are in your game. This option opens a a web window in Studio and navigates to the developer products configuration page on ROBLOX. On this page you can add new products or edit existing ones. Once a developer product is added, it will show up in the list of developer products in the game explorer window. Right clicking on a product in this list allows you to rename the products which is mainly used to help you organize your products.
For more information on how Developer Products work, see Developer Products.
The third section in the Game Explorer is for all of the images in your game. Right clicking on Images allows you to upload either a single or multiple images to your game. Adding images in this way will both add the image to your list of images and will also publish the image as a decal.
Once an image has been added to the list of images in the game explorer it can be quickly used inside of one of the Game's places. Double clicking on an image in the game explorer will add it to the currently selected object as a decal. If instead you need to use the image in a different type of instance, such as a Texture or ImageLabel, the image can be added in the properties of the instance. For example, the ImageLabel instance has a property called Image. If you select an ImageLabel and open the Properties window, clicking on the Image property in the list will open a dialog where you can add any image already in the Game Explorer window. You can also add an image in this dialog which will automatically add it to the game explorer.