In the trinocular port, there's an eyepiece, which I forget the magnification of afraid. And to that port I added this - https://www.alanwood.net/olympus/photomicro-adapter-l.html and then used an OM to EF mount converter, which the Canon camera directly attached to.

I've since bought a microscope imager, that provides an output over USB. But I think I need to remove the OM converter, and get a shorter adapter to successfully attach to the microscope C-Mount.