It should work the same way as for other roms, except that this one already has signature spoofing included (probably needed if you want to use microG instead of Gapps), see the first post of this thread for instructions how to use it with microG.
If you want to use NanoDroid systemless, I suggest using Magisk 16.6 beta, it should work flawlessly.
For the installation process of NanoDroid, you should switch to
it's thread.
There are too many possible setup scenarios to answer here.
I personally only use the custom microG apks's by
@Setialpha (many thanks for it by the way) to pass safetynet, because I want them as "real" (user) apps, so I do not need to reinstall the packages, that rely on googles push-service, like e.g. Threema, if I break Magisk while testing it (happens from time to time, while debugging in the internal test group).