What I'm seeing since the start of the thread is that Romalous is clearly starting his first Ren'Py game from the wrong end, biting a chunk too large for him to swallow or even chew through.
Romalous
When you are such a beginner that you don't seem to understand some programming basics like comments/remarks and clearly have no idea about what the code you are just basically copying from others actually does, you shouldn't waste your time trying to completely redesign Ren'Py UI.
Ren'Py has a highly functional default UI that you can redesign or if you are really ready, replace later on, when you already have some idea about what you are doing. But right now what it looks like to me is that you have removed the default UI and its image files and you are trying to create your own just by following a "tutorial" made by someone who also has no idea what he's doing.
If you really want to get started with Ren'Py and create your game in Ren'Py, start from creating the game content instead. Writing a linear or mostly linear game script in Ren'Py is much easier and gives you a chance to start from the easier tasks, get acquainted to programming basics and Ren'Py documentation and other Ren'Py games. Try to read default Ren'Py files in the game subfolder with the help of Ren'Py documentation, try to understand what is happening in there. And use those files as a base for your own design later as others already suggested.
You don't seem to be ready for the task at hand at the moment. Learn to sail before you try to design your own sail boat without any previous knowledge of sailing.
