> They documented in language reference. Language reference is not intended to be introductory course for early start. So it may not order material in structured way with crosslinks.
I am not sure what "language reference" you are talking about. I made my remark about the "Lua Reference Manual". Observe the last word in that title. In case you have not read this document, it does, as already mentioned by others, have cross-references and introductory material. Surely a few more words and perhaps an example would not break its current style.