Batch Converting RTF to Markdown?

Anyone have any help, tools, advice, etc. on batch converting RTF to Markdown in MacOS? I've used Automator a little but when I tried the advice in this thread , I couldn't get it to work. I'd love some advice on how I can handle this. I was able to install the linked services from Brett Terpstra, though they don't really show up in Quick Actions or in Automator, but only in the Touch Bar controls for some reason. When I try to install the RTF to Markdown service from the thread, it doesn't seem to show up in Services or Quick Actions. When I drag the service into Automator, and try to run it, I just get an error. I truly don't know what I'm doing wrong or how to get this to work. Any help would be greatly appreciated. Thanks!