AppShell.xaml

<FlyoutItem
    Title="Item Search"
    FlyoutDisplayOptions="AsSingleItem"
    Route="Items_Search">
    <Tab Title="Item Search" Route="item_search">
        <ShellContent
            Title="Item Search"
            ContentTemplate="{DataTemplate local:ItemSearchPage}"
            Route="item_search" />
    </Tab>
    <Tab Title="Item Details" Route="item_details">
        <ShellContent
            Title="Item Details"
            ContentTemplate="{DataTemplate local:ItemDetailPage}"
            Route="item_details" />
    </Tab>
</FlyoutItem>