If you are using C# for your project then there is a small convenience wrapper around the Dialogue Manager.
First, add the namespace:
using DialogueManagerRuntime;
Then you can load a dialogue resource and show the example balloon:
var dialogue = GD.Load<Resource>("res://example.dialogue");
DialogueManager.ShowExampleDialogueBalloon(dialogue, "start");
Or manually traverse dialogue:
var line = await DialogueManager.GetNextDialogueLine(dialogue, "start");
The returned line is a DialogueLine
and will have mostly the same properties to the the GDScript version.