popup window on my map Fragment android studio

Question

can anyone help me with this i want to show a popupwindow on top of my map fragment when i click on a button it will display a popupwindow that contains text for example the text will be how the user will navigate the map

public class FirstFragment extends Fragment {

        public FirstFragment() {
            // require a empty public constructor
        }
    
        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
            // Inflate the layout for this fragment
            View rootView = inflater.inflate(R.layout.fragment_first, container, false);
                    SupportMapFragment mapFragment = (SupportMapFragment) getChildFragmentManager().findFragmentById(R.id.maps);  //use SuppoprtMapFragment for using in fragment instead of activity  MapFragment = activity   SupportMapFragment = fragment
                mapFragment.getMapAsync(new OnMapReadyCallback() {
                    public void onMapReady(@NonNull GoogleMap googleMap) {
                        GoogleMap mMap = googleMap;
                        mMap.getUiSettings().setMyLocationButtonEnabled(true);
                        mMap.setMapType(GoogleMap.MAP_TYPE_NORMAL);
                        mMap.getUiSettings().setZoomControlsEnabled(true);
                       mMap.setBuildingsEnabled(true);
                        mMap.setInfoWindowAdapter(new CustomInfoWindowAdapter(requireContext()));
                       mMap.setMapStyle(
                                MapStyleOptions.loadRawResourceStyle(requireContext(), R.raw.style));
    
                        CameraPosition googlePlex = CameraPosition.builder()
                                .target(new LatLng(14.5768, 121.0332))
                                .zoom(15)
                                .bearing(0)
                                .tilt(60)
                                .build();
    
                        mMap.animateCamera(CameraUpdateFactory.newCameraPosition(googlePlex), 4000, null);
                        mMap.addMarker(new MarkerOptions()
                                .icon(bitmapDescriptorFromVector(getActivity(), R.drawable.ic_baseline_location_city_24))
                                .position(new LatLng(14.5768, 121.0332))
                                 .title("Mandaluyong");
    
                        KmlLayer layer = null;
                        try {
                            layer = new KmlLayer(mMap, R.raw.mandaluyong, getContext());
                        } catch (Exception e) {
                            e.printStackTrace();
                        }
                        for (KmlPlacemark placemark : layer.getPlacemarks()) {
    
                        }
    
                        layer.addLayerToMap();
                        mMap.setOnMapLongClickListener(new GoogleMap.OnMapLongClickListener() {
    
                            @Override
                            public void onMapLongClick(LatLng point) {
                                mMap.addMarker(new MarkerOptions()
                                        .position(point)
                                        .title("Home")
                                        .snippet("Your PlaceMarker!!!"));  

this is the xml file i've added a floating action button on it now when click it i want to display a popup window that will show on top of my map fragment ive tried different things and it crashes or doesnt show the popup ive decided to ask here because i am stuck in this part

    }
   <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="match_parent"
    tools:context=".MainActivity"
    xmlns:app="http://schemas.android.com/apk/res-auto">

    <fragment
        android:id="@+id/maps"
        android:name="com.google.android.gms.maps.SupportMapFragment"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />


    <com.google.android.material.floatingactionbutton.FloatingActionButton
        android:id="@+id/infobutton"
        android:src="@drawable/ic_baseline_info_24"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentEnd="true"
        android:layout_alignParentRight="true"
        android:layout_alignParentBottom="true"
        android:layout_marginStart="30dp"
        android:layout_marginTop="30dp"
        android:layout_marginEnd="2dp"
        android:layout_marginRight="2dp"
        android:layout_marginBottom="97dp"
        android:clickable="true"
        android:rotation="0" />

    <FrameLayout
        android:layout_width="300dp"
        android:layout_height="300dp"
        android:layout_marginLeft="60dp"
        android:layout_marginTop="300dp">
    </FrameLayout>
</RelativeLayout>

here are the java and xml files of the map fragment that i used
[maps app pic][1]


  [1]: https://i.stack.imgur.com/xaBIR.png