Kotlin Android - How to set app window size for chrome book/ os

Question

I made a stand alone andoird app w/c is to be used in a chromeOS desktop. I used Kotlin and when I installed the app and when it runs, it goes full screen and I have to adjust it down to the desired size. I think this is because of match_parent in my xml:

<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"

I just want it to open up at a fixed size, probably a 4th of the monitor size. Thanks for any help.