First layout doc (#784)

Author: ClementPasteau

docs/gdevelop5/all-features/resources-loading/index.md

@@ -9,7 +9,7 @@ title: Resources loading
 
 ## Understand how resources are loaded
 
-When a game starts a loading screen is shown while resources for the first scene (the one with a flag) are downloaded. It also includes resources used by global objects.
+When a game starts a loading screen is shown while resources for the first scene are downloaded. It also includes resources used by global objects. The first scene is the one marked with a flag (right-click a scene in the [project manager](/gdevelop5/interface/project-manager) and choose **Set as start scene**); if none is set, it's the first scene in the list.
 
 The resources used by other scenes are downloaded in background while users interact with the first scene, a game menu for instance.
 

docs/gdevelop5/interface/index.md

@@ -104,7 +104,7 @@ To close a project, click the three-dot menu on the project's card and select "C
 
 ### 2. Scene editor
 
-The **Scene editor** is where you design and build game levels and menus by placing and configuring objects. The first scene in the list is loaded when the game starts.
+The **Scene editor** is where you design and build game levels and menus by placing and configuring objects. By default, the first scene in the list is loaded when the game starts; you can make any scene the start scene by right-clicking it in the [project manager](/gdevelop5/interface/project-manager) and choosing **Set as start scene**.
 
 Learn more about the scene editor [here](/gdevelop5/interface/scene-editor).
 

docs/gdevelop5/interface/project-manager/index.md

@@ -15,7 +15,7 @@ You can fold and unfold each category by clicking on the small arrow next to eac
 
   * **1. Game settings:** This is where you can customize the global settings of the game. For example, the default size of the game window or the package name for Android and iOS. You can see [all settings in "Properties"](/gdevelop5/interface/project-manager/properties). You can also [set the icons for your game](/gdevelop5/interface/project-manager/icons) and [manage the resources](/gdevelop5/interface/project-manager/resources) from the game.
 
-  * **2. Scenes:** Scenes are the different screens and levels in your game. Everything in GDevelop is created in [scenes](/gdevelop5/interface/scene-editor).
+  * **2. Scenes:** Scenes are the different screens and levels in your game. Everything in GDevelop is created in [scenes](/gdevelop5/interface/scene-editor). By default, the first scene in the list is loaded when the game starts. To start the game from a different scene without reordering the list, right-click that scene and choose **Set as start scene** (the start scene is then marked with a flag).
 
   * **3. Extensions:** Extend GDevelop and make your objects and logic more modular by creating **custom behaviors**, new actions, conditions, expressions, or even custom objects using events. [Read more about extensions](/gdevelop5/extensions/create) to learn how to create them, use them in your game and share them.