In case you want to export the game as an Android .APK "without Android Studio running".
Here is what you need:
1. GMS Android export module
2. Android "SDK Manager" (to download SDK tools, API etc), the files must be available on your computer so that when the GMS compiles, it can use them.
3. Android SDK Location is set up on GMS (after downloaded it on number 2.)
4. Android NDK Location is set up on GMS
5. Java SE Development Kit (JDK) installed and is set up on GMS
6. Set Private Keystore File
And if you are having trouble with "Device Setup For Android/Enable USB Debugging/Port" and all of those settings, just export it as .APK and manually transfer the .APK and test it on your Android device. I just do number 1-6, and can test my game without Android Studio.
The guide is clear there, my method is from that page, but to make it simpler i do not want to use a connected device. I skip the Device Setup For Android/connecting/port. I just build an .apk, and manually install it on device