Unix Version 7 'learn' command (CAI) - additional configuration necessary?

I'm going through the 'Unix Programming Environment' classic by Kernighan and Pike. I discovered there was a very interesting command written by Kernighan and someone else called learn for computer aided instruction on Unix subjects like editing, macros and even C in version 7 and, it seems some of the BSD's. I've got a copy of Version 7 up and running in SimH to have a mess around with this stuff and it does indeed have a functioning learn command. However, it only gives the introduction, which asks you to choose a subject/lesson - when you type in 'files' etc, it just returns "sorry, there is no lesson named ..." or similar. There ARE lessons, or files called files.a, macros.a in the /usr/lib/learn directory of the version I got from the simh website. Does this mean I have to do some additional setup before the lessons are ready to use? Or, perhaps the lesson scripts aren't there in this copy? At the moment, I haven't yet created a new user, seeing as the default was dmr with no password. Someone has asked about this before, but more in the direction of installing it on a modern system. Anyone know if there's a Unix I could use with simh that definitely does have this and with working lessons?