<?xml version="1.0" encoding="utf-8"?>

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/activity_main"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="pl.kursandroid.helloworld.MainActivity">

⎗
✓
<Button
    android:id="@+id/button3"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentStart="true"
    android:layout_marginStart="149dp"
    android:layout_marginTop="100dp"
    android:text="Button" />

<Button
    android:id="@+id/button4"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_below="@id/button3"
    android:layout_alignStart="@id/button3"
    android:layout_marginStart="19dp"
    android:layout_marginTop="43dp"
    android:text="Button" />

</RelativeLayout>

Warning