There is nothing specific for ILE RPG. Subfiles work just the same in ILE languages (RPG, COBOL, C) as they do under the OPM compilers. The same instructions do the same things.
The best thing for you to do if you want to learn more about subfiles is to get the Book called “SUBFILES IN RPG IV (Rules, Examples, Techniques, and other Cool Stuff)”
This book is a great book to read and it only relates to Subfiles. Show everything from Subfiles, Windows, and embedded SQL into subfile and other cool tricks like a toggle functions and update, delete, add, and display records.
Its a great book and this is how I learned subfiles..
also here is an example but its not a very good one.
I would show you some of my work, but I work for a company thats very confidential.
I hope this helps.