Android Studio installs all versions of the NDK in the android-sdk /ndk/ directory.

Where can I find android NDK?

Open your Android Studio Preference (or “File->Settings”) > Appearance & Behavior > System Settings > Android SDK. You can find the path to your SDK and NDK, which is in the same directory.

What is android NDK path?

The $ANDROID_NDK in the instructions is a placeholder meant to be replaced with the path to your NDK directory. If that directory is already in your path, you should only have to type ndk-build .