docs: ✏️ add to README.md info on how to find drilldowns

x-pack/examples/ui_actions_enhanced_examples/README.md

@@ -1,12 +1,23 @@
 # Ui actions enhanced examples
 
-To run this example, use the command `yarn start --run-examples`.
+To run this example plugin, use the command `yarn start --run-examples`.
 
 
 ## Drilldown examples
 
 This plugin holds few examples on how to add drilldown types to dashboard.
 
+To play with drilldowns, open any dashboard, click "Edit" to put it in *edit mode*.
+Now when opening context menu of dashboard panels you should see "Create drilldown" option.
+
+![image](https://user-images.githubusercontent.com/9773803/80460907-c2ef7880-8934-11ea-8400-533bb9d57e36.png)
+
+Once you click "Create drilldown" you should be able to see drilldowns added by
+this sample plugin.
+
+![image](https://user-images.githubusercontent.com/9773803/80460408-131a0b00-8934-11ea-81e4-137e9e33f34b.png)
+
+
 ### `dashboard_hello_world_drilldown`
 
 `dashboard_hello_world_drilldown` is the most basic "hello world" example showing