I would try the older method first. Unplug for at least 10 seconds. Holding the set button plug in and it will start beeping. Keep holding the set button until it stops beeping. Then release set button. Will double beep in a short time. reset complete.
If that does not work follow the flow chart in the full manual. Sequence of set button pushes and LED flash patterns.
I don't know if the manuals don't have a link on their sales pages anymore. Usually under the Manuals Tab on the modules sales page.
Discontinued module maybe harder to find. You probably can use the documentation page on the Insteon.com site and use the search line to get information on the module in question. https://www.insteon.com/support#documentation
Though you probably will not find the older revisions of the modules users guides. Glad I archived all of them as I found them.