For purposes of the tutorial level and the potential of dialogue added into the game, I have added signs that pull up dialog boxes and display messages. (I wanted to upload this all as a video, but I didn't want to upload it to a site and then share the link here. Instead of this, I've done the boring, lame way of just posting three different screenshots.) It's based on a basic tutorial from YouTube:

Godot Dialog Box Tutorial

It's definitely worth a watch. It's very minimal though. It doesn't handle options or any branches. It's just for the main basics.