First, this video has a good instruction guide.
This video is about How to Setup DJI CrystalSky Monitor for Autel Explorer App for Use with Autel Evo II Pro. Includes detailed instructions on how to get Google Maps working on the Autel Explorer app running on a CrystalSky monitor attached to an Evo II remote controller. Google Maps works great now, but was a little tricky (see video). The video also discusses using the FlyHighUSA CrystalSky monitor DJI adapter mount and it concludes with a comparison of the usability/appearance of the CrystalSky 7.85" Ultra Brightness monitor, the built-in Evo II OLED display and the iPhone XS Max OLED display in bright sunlight.
NOTE: It may take 15-20 minutes to get Google Maps screen on Autel Explorer app to display a live map of your aircraft's and remote controller's current GPS location the FIRST time you attempt to get everything running after following all instructions on this video. But Google Maps will start working immediately every time after that. Also, to terminate the "Unfortunately, Google Play Services has stopped" messages from continuously popping up on the CrystalSky, EVERY time you turn on the CrystalSky monitor, Evo II remote controller and the Evo II aircraft, you MUST go into Settings, Location on the CrystalSky monitor and turn ON location services with the little slider switch. And be sure to also turn on WiFi in your CrystalSky settings and either link to a nearby internet WiFi service or to your mobile phone's hotspot in order to get continuous live Google Map updates while flying your Evo II. You can cache maps ahead of your flight as well.
READ THESE INSTRUCTIONS BEFORE PROCEEDING!
This is an unsupported installation, proceed at your own risk. Blue Skies assumes no responsibility.
There are three APK files that need to be downloaded and installed. In the CrystalSky browser, click on each link below and a new browser tab will open for each file.

Autel Explorer App (direct form Autel)
Google Play Services (47.63 MB)
Google Play Store (14.57 MB)
The first two files will require you to click the Download Anyway button due to their size. The third file will automatically start downloading. The browser will not inform you the download started.
Go to the Download app in the CrystalSky Settings to install these files
After install, DO NOT OPEN any of the Google APK's, they are being installed ONLY.
The downloaded files will be named with the Google Drive ID name instead of the actual file name.
Click on the APK files one by one to install, starting with the largest file first (73.18 MB) and ending with the smallest file (14.57 MB). DO NOT OPEN these after install, just click DONE.
Start Autel Explorer from the Apps menu. It may take a short while the first time you start it.
You will get a warning message that says, "Unfortunately, Google Play Services has stopped" each time you start the CrystalSky. Unfortunately there is no current workaround for this, just click 'OK' to close the message.
Go into the CrystalSky Settings -> Location and ensure the toggle is ON
Reboot your CrystalSky.
You should now have Google Maps in Autel Explorer on the CrystalSky.