How to start/ launch application at boot time Android

I would like to launch my app when my tablet starts, so that the main activity of my app is the first thing that the user see when they start the tablet.
I've read about LauncherActivity but I don't understand how to use it.
Can anyone help me with suggestions, links or tutorials for this?
Is LauncherActivity the best way or are there alternatives?

These lines of code may be helpful for you...

Step 1: Set the permission in AndroidManifest.xml

<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />

Step 2: Add this intent filter in receiver

<receiver android:name=".BootReceiver">
    <intent-filter >
        <action android:name="android.intent.action.BOOT_COMPLETED"/>
    </intent-filter>
</receiver>

Step 3: Now you can start your application's first activity from onReceive method of Receiver class

public class BootReceiver extends BroadcastReceiver {

   @Override
   public void onReceive(Context context, Intent intent) {
       Intent myIntent = new Intent(context, MainActivity.class);
       myIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
       context.startActivity(myIntent);
   }

}

If you want to start the app when the tablets starts, you need to listen to the BOOT_COMPLETED action and react to it. BOOT_COMPLETED is a Broadcast Action that is broadcast once, after the system has finished booting. You can listen to this action by creating a BroadcastReceiver that then starts your launch Activity when it receives an intent with the BOOT_COMPLETED action.

Add this permission to your manifest:

<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />

Create a Custom BroadcastReceiver in your project:

public class MyBroadCastReceiver extends BroadcastReceiver {

    @Override
    public void onReceive(Context context, Intent intent) {

        if(intent.getAction().equals(Intent.ACTION_BOOT_COMPLETED)){
            Intent i = new Intent(context, MyActivity.class);
            i.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            context.startActivity(i);
        }
    }
} 

Then modify your manifest file by adding the BroadCastReceiver to the Manifest:

<receiver android:name=".MyBroadcastReceiver">
    <intent-filter>
       <action android:name="android.intent.action.BOOT_COMPLETED" />
    </intent-filter>
</receiver>

Answer by @vishesh chandra is correct. But on some device doesn't work because app was installed on external storage by default. Please ensure that you specify

android:installLocation="internalOnly"

otherwise you will not receive any Boot Complete actions if the app is installed in the SD card. Add this into application tag in manifest.xml file and it will work.

Usage:

<application
        android:name=".Data.ApplicationData"
        android:allowBackup="true"
        android:hardwareAccelerated="true"
        android:icon="@mipmap/ic_launcher"
        android:installLocation="internalOnly"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/Theme.AppCompat.Light.NoActionBar.FullScreen">
        <!--activities, services...-->
</application>

I would like to add one point in this question which I was facing for couple of days. I tried all the answers but those were not working for me. If you are using android version 5.1 please change these settings.

If you are using android version 5.1 then you have to dis-select (Restrict to launch) from app settings.

settings> app > your app > Restrict to launch (dis-select)

please see picture.