The instructions in that “post #282” worked back then (in 2018), but can’t work now, because the plugin has evolved since then, so when an instruction from 3 years ago says “add something to line 62”, in 2021 the line number will be absolutely out of place.
I’ve recorded a video on a broader subject, but in that video I perform the necessary changes to the plugin that add a second text field. It’s a long video, but the second text field is already added and is functional by 11th minute, so watch it and do what I do: https://www.youtube./watch?v=dpxErm–dvE
As for other changes you’re trying to make. The “demo dialogue widget” is just that - a demo. If it doesn’t fit your needs, then you can alter it if you can, or just write your own. I’d recommend the latter for you. 99% of the plugin is in the editor. 1% is the widget. Just write your own widget, this way you’ll know exactly what lives where and why. All the API is exposed, and you can look at the demo widget to look for examples of how to interact with the dialogue asset.