is there a document to read for both how to reference sources and whys?

Hi,

as I said at another thread, almost (or already) all of the sources I have come across until now are telling how to reference with samples. But they can't or do not respond questions whether that would be required or not for specific cases.

More clearly I would ask a source which may respond my questions on referencing, but not to be expert on the issue or on the subject matter of this literature, I just want to make zero failure when I reference any source.

Thanks.

additional information: currently I do not want to attend any university MSc or PhD program. One member said that the kind of info I look for here would generally be provided at universities by training and as I said I do not want to enroll any program currently for this aim.