No worries, done.
I would also point you to a few existing threads, to familiarise yourself with the concept of using Scrivener to generate technical formats. The idea is to generate the file itself, so that it can be processed in the correct engine (xelatex or whatever). Scrivener can automate that for you, as you will discover in some of these threads. You can tell LaTeX to typeset the .tex file that Scrivener helps you generate, so that you get a .pdf instead.
What we are looking at here is changing our perspective of what Scrivener is, from a powerful writing tool that has a rather basic text editor with a few word processing functions, to a powerful writing tool that is used to assemble plain-text formats. That could be LaTeX, that could be DITA, DocBook, PrinceXML or any number of plain-text oriented markup formats. The template you are playing with is, although of practical use to many, a tech demo of this concept.
Another way of thinking about it: Scrivener is acting more like Visual Studio Code here: it can help you create the material you will typeset in xelatex—only instead of a GUI built for programmers, it is a GUI built for writers—and with its comprehensive engine for exporting (the compiler) we can negate how much manual markup we use to a great degree—to the point that some might even write in Scrivener as though they were using a word processor, with barely ever having to use raw LaTeX syntax.
But you can, and that’s where it gets powerful. If Scrivener’s footnote feature is too simple to stack footnotes together adjacent to one another, then you can just type in the \footnote{...} stuff yourself right in the editor, while otherwise depending on Scrivener’s ability to convert its footnotes to that same syntax, for more basic cases elsewhere.
Further Reading
- Some overall thoughts on Scrivener’s role as a document assembly tool.
- How the preamble works in the LaTeX project template.
- And here is the thread from which the LaTeX template arose. It is perhaps only of academic interest now, as much of that thread is early feedback on the template and refinements made to it as a result. However it does go into the overall design philosophy of using it, so maybe you will find it helpful.