Step 3) This is what your file should look like

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


    <LinearLayout
    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:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/colorPrimaryDark"
    android:gravity="center|top"
    android:orientation="vertical"
    tools:context="MainActivity">


    <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:tools="http://schemas.android.com/tools"
        android:layout_width="match_parent"
        android:layout_height="200dp"
        android:layout_gravity="top"
        tools:context=".MainActivity">

        <EditText
            android:id="@+id/editText"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentStart="true"
            android:layout_alignParentLeft="true"
            android:layout_alignParentTop="true"
            android:layout_alignParentEnd="true"
            android:layout_alignParentRight="true"
            android:layout_marginStart="0dp"
            android:layout_marginLeft="0dp"
            android:layout_marginTop="0dp"
            android:layout_marginEnd="0dp"
            android:layout_marginRight="0dp" />

        <Button
            android:id="@+id/buttonStart"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@+id/editText"
            android:layout_alignParentStart="true"
            android:layout_alignParentLeft="true"
            android:onClick="onClickStart"
            android:text="Begin" />

        <Button
            android:id="@+id/buttonSend"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@+id/editText"
            android:layout_toEndOf="@+id/buttonStart"
            android:layout_toRightOf="@+id/buttonStart"
            android:onClick="onClickSend"
            android:text="Send" />

        <TextView
            android:id="@+id/textView"
            android:layout_width="50dp"
            android:layout_height="100dp"
            android:layout_below="@+id/buttonSend"
            android:layout_alignEnd="@+id/editText"
            android:layout_alignRight="@+id/editText"
            android:layout_alignParentStart="true"
            android:layout_alignParentLeft="true"
            android:layout_alignParentBottom="true" />

        <Button
            android:id="@+id/buttonStop"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@+id/editText"
            android:layout_toEndOf="@+id/buttonSend"
            android:layout_toRightOf="@+id/buttonSend"
            android:onClick="onClickStop"
            android:text="Stop" />

        <Button
            android:id="@+id/buttonClear"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@+id/editText"
            android:layout_toEndOf="@+id/buttonStop"
            android:layout_toRightOf="@+id/buttonStop"
            android:onClick="onClickClear"
            android:text="Clear" />
    </RelativeLayout>


    <TextView
        android:layout_width="match_parent"
        android:layout_height="30dp"
        android:layout_gravity="center"
        android:gravity="center"
        android:text="Vodka Drinks"
        android:textColor="@color/White"
        android:textSize="20dp"
        android:textStyle="bold" />

    <in.goodiebag.carouselpicker.CarouselPicker
        android:id="@+id/carouselPicker1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="20dp"
        android:layout_marginBottom="20dp"
        android:background="#FFF"
        app:items_visible="three"

        />

    <TextView
        android:layout_width="match_parent"
        android:layout_height="30dp"
        android:layout_gravity="center"
        android:gravity="center"
        android:text="Rum Drinks"
        android:textColor="@color/White"
        android:textSize="20dp"
        android:textStyle="bold" />

    <in.goodiebag.carouselpicker.CarouselPicker
        android:id="@+id/carouselPicker2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="20dp"
        android:layout_marginBottom="20dp"
        android:background="#FFF"
        app:items_visible="three" />

    <TextView
        android:layout_width="match_parent"
        android:layout_height="30dp"
        android:layout_gravity="center"
        android:gravity="center"
        android:text="Gin Drinks"
        android:textColor="@color/White"
        android:textSize="20dp"
        android:textStyle="bold" />

    <in.goodiebag.carouselpicker.CarouselPicker
        android:id="@+id/carouselPicker3"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="20dp"
        android:layout_marginBottom="20dp"
        android:background="#FFF"
        app:items_visible="three" />


    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:background="@drawable/buttonstyle"
        android:onClick="ShowPopup"
        android:text="Order Drink"
        android:textColor="@color/colorAccent" />

</LinearLayout>