I am a Lily confused about .ly file structure

[John Sellers]

I have gotten my feet wet with LilyPond, but I'm going nuts every time want do do something new.

Unfortunately almost everything is lifted out of context as an isolated, clearly explained example, or embedded in a small complete file which is almost certainly different in structure from the structure of my particular .ly file.

There are four tasks I am having lots of trouble with:

1) Immediately recognizing the top level semantics of many of the .ly files I look at without much head scratching or failure.

2) Knowing how to embed an arbitrary example of behavior that I want in my particular .ly file, which more often than not, is differently structured from the example.

3) Knowing at which point in the .ly file a particular piece of code has to go in order to be recognized and parsed and do what I expect it to do.  Example, \newpage, only after much wasted time I figured it is supposed to be embedded in note representation.  I didn't know which part of the file was music representation data and which part was something else that is not sequentual such as headers.  \newpage at the beginning or end of a score seems to be a no-opt which is really confusing without a solid understanding of .ly file structure.

4) Knowing when a particular syntax is allowed for my piece of code.  Example, things starting with a back slash can be assigned using an equal sign in front of them...sometimes and sometimes not. Also assigned variables or what ever they are, can be directly substituted for the code and the code can be put elsewhere...scoping rules?  What scoping rules?

All these are problems of .ly syntax structure and semantics relating to context and overall structure, and are not clear from the almost pervasive approach of specific examples that dominate documentation and tutorials.

So my question is, where do I look to find a concise complete description the answer to these questions so I don't have to read volumes before I can learn to parse any .ly file?