Every scene you load on startup.txt must exist in form of a txt file.
*scene_list
chapter1
chapter2
chapter3
for example, all those chapter#.txt have to exist like actual files in the same location as your startup.txt.
You can divide your chapters into different files, with multiple scenes inside each one of them, or you can make a file for each scene (which I don’t recommend).
The command *goto jumps to a *label inside the same file, so you don’t need to switch from file to file every time you need to *goto somewhere else.
The way I use it, and the way I guess most of us do, is using *goto to jump to different *label scenes of your story inside the same file, like for example in chapter1.txt, and only *goto_scene or *finish to jump to another chapter if you reach the end of that chapter.
So you can have several things happen in chapter1 after you jump to chapter2. You can divide it in the way you want, as the day has passed, some important event that marks the end of the chapter, or maybe some more complex scene you want to keep separated from the rest, it’s up to you and how you organize your plot and the way you structure your game.
If you also need help with that I’ll recommend you use some mind-map tool to lay out your story so you can have a visual representation of it.
Here are some links that have a lot of information that may help you
And this is a tool I found very helpful to take notes and keep track of everything, and even create mind maps with the ability to link everything together.