Thanks, @62qBruv. The first part of that video provides an overview of how the UI system works. The second part zips through a visual novel-style setup to keep the video to a reasonable length. You can watch it to get a general idea of some things you can do, but instead of following it step-by-step in your project, I recommend the steps below:
First make sure you've at least gone through the
Quick Start Tutorial.
Create a dialogue database, and make sure it's assigned to the Dialogue Manager's
Initial Database field. Then edit the database in the Dialogue Editor window. On the Actors panel, add actors for the two characters. You can use the default Player actor for whichever charcter is the player. Assign the characters' portrait images (the big images in the foreground of your screenshot) to the actors'
Portrait Sprite fields. Then write a short test conversation.
Assign the
VN Template Standard Dialogue UI prefab to the Dialogue Manager GameObject's
Display Settings > Dialogue UI field. A pop-up window will ask if you want to Add Instance or Use Prefab. Click
Add Instance. This will add a copy of the UI as a child of the Dialogue Manager's Canvas.
From there, test it out. Add a Dialogue System Trigger to start the conversation. (See the Quick Start tutorial for info on Dialogue System Trigger.) You can set it to OnStart so it starts the conversation immediately. Check if the dialogue UI looks similar to what you want. If so, you can exit play mode and customize the UI. For example, you could make the Portrait Image components bigger, change the background of the Text Panel to black, move it all the way to the bottom, etc.
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Spreadsheets (Google Sheets) are not a good format to import conversations. Conversation trees are not structured like spreadsheets. They are structured like networks, with nodes (lines of text) pointing to other nodes, and sometimes looping back to previous nodes. The Dialogue System can import from several other formats that are better at defining conversations: articy:draft, Aurora, Chat Mapper, TalkIt, Twine, and a custom plain text format called JLC. However, until you get comfortable with the Dialogue System itself, I recommend writing a few test conversations in the built-in Dialogue Editor window.
That said, the Dialogue System has good support for Google Sheets when exporting and importing
localization files -- that is, translations for different languages. In this case, since the conversations' structures are already defined in the dialogue database, it's acceptable to use a spreadsheet just to hold the lines of text.
If you have any questions about any of this, just let me know. I'm here to help.