Feature layer readme improvements (#26)

* Update readme.md

* Apply suggestions from code review

Co-authored-by: Jade Huang <jadehuang@esri.com>
Co-authored-by: Andy Ren <aren@esri.com>

Co-authored-by: Jade Huang <jadehuang@esri.com>
Co-authored-by: Andy Ren <aren@esri.com>

Author: 3 people

sample_project/Content/SampleViewer/Samples/FeatureLayer/readme.md

@@ -1,20 +1,32 @@
-# Feature Layer
+# Query a feature layer
 
 Query objects from a feature layer and show them on the map.
 
 ![Image of Feature Layer Sample](FeatureLayer.jpg)
 
+## How to use the sample
+
+1. Open the **FeatureLayer_lvl** level.
+2. Click on the **ArcGISMapActor** in the Outliner panel.
+3. Set your API key under Authentication section in the Details panel.
+4. Click play and select a stadium from the list.
+
 ## How it works
 
-1. Create an http request in the project's gamemode.cpp and gamemode.h
-2. Using the UE_LOG, confirm that you are gathering the data properly.
-3. Create a new Blueprint class and cast to the gamemode.
-4. Using the cast, get the data stored from the http request. 
-5. Spawn in a new actor of the class you created above and set the data accordingly.
+1. Create a new C++ class and make a http request to [query a feature layer](https://developers.arcgis.com/rest/services-reference/enterprise/query-feature-service-.htm). 
+2. Create a new Blueprint Actor class
+   - Create the event to place the stadium data returned from the feature layer.
+   - Create a function to spawn the actor according to the stadium `NAME`.
+   - Create a function to apply different materials according to the `LEAGUE` value.
+   - Attach the [**ArcGIS Location Component**](https://developers.arcgis.com/unreal-engine/maps/location-component/) to the static stadium mesh model.
+   - Create a function to place the static mesh model on the `geometry`'s `coordinates` location returned by the feature layer query and the height calculated by [raycasts](https://docs.unrealengine.com/5.0/en-US/using-a-single-line-trace-raycast-by-channel-in-unreal-engine/).
+3. Create a widget for the viewport so users can select a stadium from the list fed from the feature service.
+
+Note: You can use `UE_LOG` to print log messages in the **Output Log** window and see if you are gathering the data properly from the feature service.
 
 ## About the data
 
-Data for all Major League Baseball Stadiums in the United States [Feature Layer](https://services.arcgis.com/P3ePLMYs2RVChkJx/ArcGIS/rest/services/Major_League_Baseball_Stadiums/FeatureServer/0/query?f=geojson&where=1=1&outfields=TEAM,NAME,LEAGUE) hosted by Esri.
+Data for all Major League Baseball Stadiums in the United States [Feature Layer](https://www.arcgis.com/home/item.html?id=f60004d3037e42ad93cb03b9590cafec) hosted by Esri. (Format the request URL for the [query](https://services.arcgis.com/P3ePLMYs2RVChkJx/ArcGIS/rest/services/Major_League_Baseball_Stadiums/FeatureServer/0/query?f=geojson&where=1=1&outfields=TEAM,NAME,LEAGUE).)
 
 Elevation data is loaded from the [Terrain 3D elevation layer](https://www.arcgis.com/home/item.html?id=7029fb60158543ad845c7e1527af11e4) hosted by Esri.