Replace Activity in Manifest.xml

You must change your manifest:

    <?xml version="1.0" encoding="utf-8"?>
    <manifest xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:tools="http://schemas.android.com/tools"
        package="bizsalt.drawer2">

        <application
            android:allowBackup="true"
            android:icon="@mipmap/gargi_blue"
            android:label="@string/app_name"
            android:theme="@style/AppTheme">
            <activity
                android:name=".SplashScreenActivity"
                android:label="XYZ"
                android:theme="@style/AppTheme">
                <intent-filter>
                    <action android:name="android.intent.action.MAIN" />

                    <category android:name="android.intent.category.LAUNCHER" />
                </intent-filter>
            </activity>
            <activity
                android:name=".LoginActivity"
                android:label="XYZ"
                android:theme="@style/AppTheme"
              />
             <activity
                android:name=".RegisterActivity"
                android:label="XYZ"
                android:theme="@style/AppTheme"
              /> 
             <activity
                android:name=".MainActivity"
                android:label="XYZ"
                android:theme="@style/AppTheme"
              />
    </application>
    </manifest>

And in your SplashScreenActivity. Put code to transit to LoginActivity:

Intent mIntent = new Intent(SplashScreenActivity.this,LoginActivity.class);
startActivity(mIntent);

Do same with other Activity