a bit confused with <manifest>

[nalnir]

I am very new to react-native and this library is in fact my first one I am using for my project.
I am a bit confused with this block of code that I am suppose to manually add to manifest:

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:tools="http://schemas.android.com/tools"
    package="com.kamera">

I have this block of code in my AndroidManifest.xml

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="roluk.carsale">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme" />
</manifest>

I don't fully understand how to add the first block of code. It says in the beginning of the manifest but I don't fully understand that.
Should I do it this way?

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:tools="http://schemas.android.com/tools"
    package="com.kamera">
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="roluk.carsale">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme" />
</manifest>

It doesn't make much sense to me to do it like that, but I'm not sure.