Elements overlapping on each other in my android studio emulator

I am new to Android Studio, when I created my app all my elements overlapped on each other. I am not sure how to edit this code. Please give me a detailed description.

Layout editor and emulator result

Code for the layout

<?xml version="1.0" encoding="utf-8"?> 
<android.support.constraint.ConstraintLayout 
    xmlns:android="schemas.android.com/apk/res/android"; 
    xmlns:app="schemas.android.com/apk/res-auto"; 
    xmlns:tools="schemas.android.com/tools"; 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    tools:context="com.example.first.anew.MainActivity"> 

    <TextView
        android:layout_width="216dp"
        android:layout_height="60dp"
        android:text="Hello World!"
        tools:layout_editor_absoluteY="16dp"
        tools:layout_editor_absoluteX="61dp" />

    <Button
        android:id="@+id/button"
        android:layout_width="100dp"
        android:layout_height="45dp"
        android:text="Login"
        tools:layout_editor_absoluteY="343dp"
        tools:layout_editor_absoluteX="177dp" />

    <TextView
        android:id="@+id/textView"
        android:layout_width="215dp"
        android:layout_height="65dp"
        android:text="username"
        tools:layout_editor_absoluteY="117dp"
        tools:layout_editor_absoluteX="61dp" />

    <android.support.constraint.Guideline
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/guideline"
        app:layout_constraintGuide_begin="20dp"
        android:orientation="horizontal" />

    <EditText
        android:id="@+id/editText"
        android:layout_width="217dp"
        android:layout_height="57dp"
        android:ems="10"
        android:inputType="textPassword"
        tools:layout_editor_absoluteY="218dp"
        tools:layout_editor_absoluteX="61dp" />
</android.support.constraint.ConstraintLayout>