For information about how plugins work on EZ_Builder, please refer to https://www.ez-robot.com/Tutorials/UserTutorials/146/1
To build and run this project, you will need to add the default references for EZ-Builder plugins (see https://www.ez-robot.com/Tutorials/UserTutorials/146/5, item 4), plus an NAudio reference that can be found in the same folder of the default references.
For information about this specific plugin, please go to https://www.ez-robot.com/EZ-Builder/Plugins/view/207
The code at TextToSpeechHelper.cs is pretty much the same as in https://github.com/Azure-Samples/Cognitive-Speech-TTS/blob/master/Samples-Http/CSharp/TTSClient.cs
Stuff happens mainly at the MainForm.cs