Minor fixes to Create New and Executable tutorials (#1486)

* Wording and filepath changes to tutorials

* Retake editor images to match v0.6

Retake editor images so that the filepaths and Brain names match what they actually are.

docs/Learning-Environment-Create-New.md

 for the Agent to move around on, a Cube to act as the goal or target for the
 agent to seek, and a Sphere to represent the Agent itself.
 
-### Create the floor plane
+### Create the Floor Plane
-3. Select Plane to view its properties in the Inspector window.
+3. Select the Floor Plane to view its properties in the Inspector window.
 4. Set Transform to Position = (0, 0, 0), Rotation = (0, 0, 0), Scale = (1, 1, 1).
 5. On the Plane's Mesh Renderer, expand the Materials property and change the
     default-material to *LightGridFloorSquare* (or any suitable material of your choice).
 
 1. Right click in Hierarchy window, select 3D Object > Cube.
 2. Name the GameObject "Target"
-3. Select Target to view its properties in the Inspector window.
+3. Select the Target Cube to view its properties in the Inspector window.
 4. Set Transform to Position = (3, 0.5, 3), Rotation = (0, 0, 0), Scale = (1, 1, 1).
 5. On the Cube's Mesh Renderer, expand the Materials property and change the
     default-material to *Block*.
 
 1. Right click in Hierarchy window, select 3D Object > Sphere.
 2. Name the GameObject "RollerAgent"
-3. Select Target to view its properties in the Inspector window.
+3. Select the RollerAgent Sphere to view its properties in the Inspector window.
 4. Set Transform to Position = (0, 0.5, 0), Rotation = (0, 0, 0), Scale = (1, 1, 1).
 5. On the Sphere's Mesh Renderer, expand the Materials property and change the
     default-material to *CheckerSquare*.
 
 The Brain object encapsulates the decision making process. An Agent sends its
 observations to its Brain and expects a decision in return. The type of the Brain
-(Learning, Heuristic or player) determines how the Brain makes decisions. 
+(Learning, Heuristic or Player) determines how the Brain makes decisions. 
 To create the Brain:
 
 1. Go to **Assets** > **Create** > **ML-Agents** and select the type of Brain asset

docs/Learning-Environment-Executable.md

 3. Using the file dialog that opens, locate the `UnitySDK` folder within the
    ML-Agents project and click **Open**.
 4. In the **Project** window, navigate to the folder
-   `Assets/ML-Agents/Examples/3DBall/`.
+   `Assets/ML-Agents/Examples/3DBall/Scenes/`.
 5. Double-click the `3DBall` file to load the scene containing the Balance Ball
    environment.
 
 to be able to control your agents from Python, you will need to put the Brain
 controlling the Agents to be a **Learning Brain** and drag it into the
-Academy's `Broadcast Hub` with the `Control`  checkbox checked.
+Academy's `Broadcast Hub` with the `Control` checkbox checked. In the 3DBall
+scene, this can be done in the Platform GameObject within the Game prefab in 
+`Assets/ML-Agents/Examples/3DBall/Prefabs/`, or in each instance of the 
+Platform in the Scene.
 
 Next, we want the set up scene to play correctly when the training process
 launches our environment executable. This means:
    * (optional) Select “Development Build” to [log debug
       messages](https://docs.unity3d.com/Manual/LogFiles.html).
 5. If any scenes are shown in the **Scenes in Build** list, make sure that the
-   3DBall Scene is the only one checked. (If the list is empty, than only the
+   3DBall Scene is the only one checked. (If the list is empty, then only the
    current scene is included in the build).
 6. Click **Build**:
    * In the File dialog, navigate to your ML-Agents directory.