First either adjust a.cmd to have correct paths to Android SDK, Android NDK and Java SDK or set them in environment variables.
Then set APK varible to desired apk package name. Use Android SDK to install build-tools and platform SDK.
Now you can use a.cmd to build, install and run the application:
a [command]
By default build, install and run .apk file.
Optional [command] is:
run - only install and run .apk file
build - only build .apk file
remove - remove installed .apk
install - only install .apk file on connected device
launch - ony run already installed .apk file
log - show logcat