Instrument Your Application Code

In the index.js file of your React application:

At the top of the file near the other import statements, add the following line of code to import the agent:
```
 import {Instrumentation} from '@appdynamics/react-native-agent';
```
1. In the same file and in the global scope, initialize the instrumentation with the following, making sure to replace <EUM_APP_KEY> with a string containing your EUM App Key.
```
Instrumentation.start({
    appKey: <EUM_APP_KEY>,
}); 
```
  Note: Whenever possible, we recommend you call Instrumentation.startin a context that permits awaiting for this async call and even enabling verbose logging for better debugging:
```
async function startInstrumentation() {
  await Instrumentation.start({
    appKey: <EUM_APP_KEY>,
    loggingLevel: LoggingLevel.VERBOSE
  });
}
```

Verify that your index.js file looks similar to the following:

import App from './src/App';
import {AppRegistry} from 'react-native';
import {name as appName} from './app.json';

import {Instrumentation} from '@appdynamics/react-native-agent';  

Instrumentation.start({
    appKey: 'YOUR-APP-KEY',
});

AppRegistry.registerComponent(appName, () => App);

(For older React Native setup builds) If you have use_frameworks! defined in your ios/Podfile, we recommend adding the following:
```
$ toggleADEUMRNStaticFramework = true
```