Egmde is a "worked example" of using Mir written to accompany a set of blog posts. It is a basic, usable graphical shell, not a not a fully functional desktop environment.
These blog posts are listed here: https://github.com/AlanGriffiths/egmde/wiki
They don’t cover aspects of a desktop environment that are not related to using Mir. Missing functionality includes: integrating into the system for screen locking & suspend, policy kit integration, internationalization, etc.
To use egmde as your desktop, select it when logging in, to run it on your desktop run "egmde".
Egmde can be configured by editing ~/.config/egmde.config or on the commandline. Options are listed with:
$ egmde --help
There's more about customizing the appearance of egmde on the Ubuntu discourse:
There is also some limited support for "remote desktop" meaning egmde can be used over
ssh's "X forwarding":
$ ssh -XC <user@host> sh -lc egmde