Hello! Back again! I was just wondering what is the best way to go about customizing the phone chat printer. I was trying to make it look at actually phone appearing on screen. I was able to play around with the dimensions enough that the messages fit the sprite, but the messages themselves are only popping up one at a time. Instead of appearing and staying on the screen, like the example in the guide. Also, what would be the best way to go about animating the phone coming onto the screen, instead of just appearing? I was hoping to give the impression that it being picked up/taken out of a pocket and being looked at.

You've probably done something wrong if they're only appearing one at a time. Check the Custom UI example project which has a functional Chat printer as well as a timestamp feature that is not included in the Naninovel package (you can copy over the script to your own project if it's useful for you). https://github.com/Naninovel/CustomUIExample

In regards to showing and hiding the printer, you can add an animation on the OnShow() and OnHide() Unity events. The above example project uses Animator for showing/hiding a calendar, that's one option and there's plenty of video tutorials on how to animate within Unity in case you fancy something more complex.