run, build and prepare

Each of the three commands contains the one before it. cordova prepare copies www into every platform, adds that platform's cordova.js and turns config.xml into native manifests; run it before opening platforms/android in Android Studio 234 . cordova build is prepare plus compile, the Gradle 19,597 run that writes platforms/android/app/build/outputs/apk/debug/app-debug.apk. cordova run builds, then installs and launches the app.

cordova build android

...
> Task :wrapper
BUILD SUCCESSFUL in 17s
...
BUILD SUCCESSFUL in 1m 4s
50 actionable tasks: 50 executed
Built the following apk(s):
   .../platforms/android/app/build/outputs/apk/debug/app-debug.apk

The first BUILD SUCCESSFUL is the wrapper task (Gradle). With several devices attached, name one: --list shows the candidates, and --target takes an adb serial or an AVD name (which it boots if needed):

cordova run android --list
cordova run android --target=emulator-5558

Available android devices:
Available android virtual devices:
book
...
BUILD SUCCESSFUL in 1m 36s
...
Deploying to emulator emulator-5558
...
INSTALL SUCCESS
LAUNCH SUCCESS

emulator-5558 is just this emulator's serial; use whatever adb devices prints, usually emulator-5554.