activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.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:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <ImageButton
        android:id="@+id/imageButton"
        android:layout_width="136dp"
        android:layout_height="136dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.145"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.203"
        app:srcCompat="@drawable/scheduler" />

    <ImageButton
        android:id="@+id/musicbutton"
        android:layout_width="136dp"
        android:layout_height="136dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.535"
        app:layout_constraintStart_toEndOf="@+id/imageButton"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.203"
        app:srcCompat="@drawable/relaxingmusic" />

    <ImageButton
        android:id="@+id/imageButton3"
        android:layout_width="136dp"
        android:layout_height="136dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.145"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/imageButton"
        app:layout_constraintVertical_bias="0.266"
        app:srcCompat="@drawable/time" />

    <ImageButton
        android:id="@+id/imageButton4"
        android:layout_width="136dp"
        android:layout_height="136dp"
        android:layout_marginStart="52dp"
        android:layout_marginBottom="248dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="@+id/imageButton2"
        app:layout_constraintHorizontal_bias="1.0"
        app:layout_constraintStart_toEndOf="@+id/imageButton3"
        app:layout_constraintTop_toBottomOf="@+id/imageButton2"
        app:layout_constraintVertical_bias="0.265"
        app:srcCompat="@drawable/tips" />

    <Button
        android:id="@+id/brainicsbutton"
        android:layout_width="136dp"
        android:layout_height="57dp"
        android:text="Meet Brainics"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.963" />
</androidx.constraintlayout.widget.ConstraintLayout>