XAML Page With Grid And Button - xaml

Question

I have a grid which will take up most of my Xamarin.Forms Page, and I want to add a button below the grid. My issue is that I am using the below syntax to add the button, however the button fills the entire page.
What do I need to change so that the button appears directly below the grid?
<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
x:Class="XF.Pages.AEI" >
<ContentView Content="{Binding ApprovedUserGrid,Mode=TwoWay}" Padding="0,30,0,0"/>
<Button Command="{Binding OkayCommand}" Text="Okay" TextColor="White"
FontAttributes="Bold" FontSize="Large" HorizontalOptions="FillAndExpand"
BackgroundColor="#088da5" />
</ContentPage>
This is C# for my grid (not where I actually bind, but the creation)
private Grid _Grid;
public Grid TestGrid
{
get { return _Grid ?? (_Grid=new Grid()); }
set
{
_Grid = value;
NotifyPropertyChanged();
}
}
EDIT
I edit code to read like this, and there are no errors, but I do not see my button on the page?
<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
x:Class="XF_Login.Pages.ApproveUsers" >
<StackLayout Orientation="Vertical" Padding="30" Spacing="40">
<ContentView Content="{Binding ApprovedUserGrid,Mode=TwoWay}" Padding="0,30,0,0"/>
<Button Command="{Binding OkayCommand}" Text="Okay" TextColor="White"
FontAttributes="Bold" FontSize="Large" HorizontalOptions="FillAndExpand"
BackgroundColor="#088da5" />
</StackLayout>
</ContentPage>

Answer 1

<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
x:Class="XF_Login.Pages.ApproveUsers" >
<StackLayout Orientation="Vertical" VerticalOptions="FillAndExpand" Padding="30" Spacing="40">
<ContentView VerticalOptions="FillAndExpand" Content="{Binding ApprovedUserGrid,Mode=TwoWay}" Padding="0,30,0,0"/>
<Button Command="{Binding OkayCommand}" Text="Okay" TextColor="White"
FontAttributes="Bold" FontSize="Large" HorizontalOptions="Center"
BackgroundColor="#088da5" />
</StackLayout>
</ContentPage>