constraintlayout_three_buttons.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/container_delivery_item"
    android:layout_width="match_parent"
    android:layout_height="match_parent"

    android:orientation="vertical">

    <Button
        android:id="@+id/button1"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginBottom="48dp"
        android:layout_marginStart="16dp"
        android:text="Button"
        app:layout_constraintBottom_toBottomOf="@+id/container_delivery_item"
        app:layout_constraintLeft_toLeftOf="@+id/container_delivery_item" />

    <Button
        android:id="@+id/button2"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="4dp"
        android:text="Button"
        app:layout_constraintLeft_toRightOf="@+id/button1"
        app:layout_constraintTop_toTopOf="@+id/button1" />

    <Button
        android:id="@+id/button3"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginEnd="16dp"
        android:layout_marginStart="4dp"
        android:text="Button"
        app:layout_constraintLeft_toRightOf="@+id/button2"
        app:layout_constraintRight_toRightOf="@+id/container_delivery_item"
        app:layout_constraintTop_toTopOf="@+id/button2"
        tools:layout_constraintLeft_creator="1"
        tools:layout_constraintRight_creator="1" />

    <android.support.constraint.Guideline
        android:id="@+id/guideline4"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        app:relativePercent="34"
        tools:layout_editor_absoluteX="139dp"
        tools:layout_editor_absoluteY="0dp" />

    <android.support.constraint.Guideline
        android:id="@+id/guideline5"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        app:relativePercent="68"
        tools:layout_editor_absoluteX="279dp"
        tools:layout_editor_absoluteY="0dp" />

    <Button
        android:id="@+id/button11"
        android:layout_width="0dp"
        android:layout_height="49dp"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="16dp"
        android:layout_marginTop="16dp"
        android:text="Button"
        app:layout_constraintLeft_toLeftOf="@+id/container_delivery_item"
        app:layout_constraintRight_toLeftOf="@+id/guideline4"
        app:layout_constraintTop_toTopOf="@+id/container_delivery_item" />

    <Button
        android:id="@+id/button12"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="16dp"
        android:text="Button"
        app:layout_constraintHorizontal_bias="0.62"
        app:layout_constraintLeft_toLeftOf="@+id/guideline4"
        app:layout_constraintRight_toLeftOf="@+id/guideline5"
        app:layout_constraintTop_toTopOf="@+id/container_delivery_item" />

    <Button
        android:id="@+id/button13"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginEnd="16dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="16dp"
        android:text="Button"
        android:visibility="visible"
        app:layout_constraintHorizontal_bias="0.33"
        app:layout_constraintLeft_toLeftOf="@+id/guideline5"
        app:layout_constraintRight_toRightOf="@+id/container_delivery_item"
        app:layout_constraintTop_toTopOf="@+id/container_delivery_item" />

</android.support.constraint.ConstraintLayout>