Joined: 23 Nov 2006 Posts: 19270 Location: Inside the Matrix
At the top of the page is a link to "IBM Manuals". The first set of material is COBOL. Pick the Language Reference for your version of cobol and search (the flashlight/tubelight near the top left) for "recording mode".
If you find something that is not clear, post what you found and your doubt about it.