Hello! im having some problems with the custom assets, i follow all the instructions but the game shows the in-puzzle level layout and the new custom text don't shows up, this is how that looks like (im testing a bit but for more i try i can't fix this) 
To disable the ui you need to tick off these options in the Scene Settings Window (Check example image below: Red is the side UI with counters, Green is the "Life Advice and Restart" UI). As for custom text, if you mean the dialogue I'll need extra context as to how its arranged in editor or a screenshot of the editor window, or a data folder so I can take a closer look.
I am back with great news, all it was that one of your files "gar_Excusemewhat" has a capital letter, which messes up the way data is read. Which is a dumb moment on my part and will be fixed in version 1.0 but if you rename it to "gar_excusemewhat" it will run like butter. Let me know if there are any more issues.