Document script execution order

Author: jgimenez

README.md

@@ -10,7 +10,12 @@ To use Bugfender in your Unity project, follow these steps:
  * You can use the Bugfender.Log() method to write logs.
 
 If you use Bugfender in a platform other than iOS or Android, any calls to Bugfender will be just ignored but other than that, your application will keep working as usual. Please note the WebGL platform is currently not supported yet, although we plan to support it in the future.
- 
+
+### Script Execution Order
+Bugfender is provided as a Prefab that you can drop into your project. Before using Bugfender, the `Start()` method of the Prefab needs to be called, so you can ensure it's available before your scripts start running by setting a **Script Execution Order** in your **Project Settings**, like so:
+
+![Script Execution Order](https://user-images.githubusercontent.com/864706/220148469-91455103-32d7-46fc-be27-c718f86dc930.png)
+
 ## How to update the libraries
 
 To update the Android library: