OK so I've had Google Home integration with HG for some time using the SmartThings developers portal as some others have done.
This is a painful route to go for any newbie and not very speedy.
However,
there is now a HG program that interfaces directly. Simply install it to the device and things programs then for each device you wish to have google control of you open the options of that device and click the GoogleHome so it can be controlled no coding involved. This is currently in the testing stages and hosted on a HG users own Pi. I'm hopeful Authinx will eventually handle the server end which would be extremely helpful.
For users interested in this you'll need a Google account (everyone has one right?) and you'll need the HG GoogleHome Program installed in HG.
To sign up for testing and more info check out this thread
https://homegenie.club/t/google-home-plugin/447I had a bit of a problem initially getting this setup but the issue was more with how my Phone was handling the account linking things.
I do believe the account linking bugs are now worked out.
Currently there are only a few of us testing this however the more testers that get involved the faster this gets put into full service.