Expecting you have the React Native development environment in place:
git clone https://github.com/react-native-community/react-native-audio-toolkit.git
cd react-native-audio-toolkit/ExampleApp
npm install
npm run start:android
git clone https://github.com/react-native-community/react-native-audio-toolkit.git
cd react-native-audio-toolkit/ExampleApp
npm install
npm run start:ios
Then start clicking the buttons, it should be quite simple.