I've seen XML before, but I've never seen anything like EDI.
How do I read this file and get the data that I need? I see things like ~, REF, N1, N2, N4 but have no idea what any of this stuff means.
One EDI guide I found says that it is based on "ANSI ASC X12/ ver. 4010". Should I search form X12?
In principle, each line is a "segment", and the identifiers are the beginning of the line is a segment identifier. Each segment contains "elements" which are essentially positional fields. They are delimited by "element delimiters".
Different segments mean different things, and can indicate looping constructs, repeats, etc.
You need to get a current version of the standard for the basic parsing, and then you need the data dictionary to describe the content of the document you are dealing with, and then you might need an industry profile, implementation guide, or similar to deal with the conventions for the particular document type in your environment.
Examples? Not current, but I'm sure you could find a whole bunch using your search engine of choice. Once you get the basic segment/element parsing done, you're dealing with your application level data, and I don't know how much a general example will help you there.