I have no idea how to use the industrial sawmill. No matter what multiblock I give it, it says that it is wrong. I have looked at Greg tech wikis and those don't work either. I am sorry if this isn't the right place for this question but I can't find any documentation on this machine.

Added the wiki label as thats where it should go.

this is also a bug though, there's not even JEI recipes for it

It is there now.
https://wiki.techreborn.ovh/doku.php?id=blocks:saw_mill