It's literally downloading a few apks and installing them. You don't even need to use adb. You can do it all within the preloaded browser that's on the tablet.
I don’t remember it being that easy when I did it 3-4 years ago. I was also a bit uncomfortable downloading the google support libraries from APKmirror, as my life is on my google account. IIRC the APKs were unsigned.
https://www.howtogeek.com/232726/how-to-install-the-google-p...