Creating the MainShell file 

We'll add the MainShell file directly to the root of the .NET Standard Library. There is no template for a shell available, so we need to add a regular content page file and make some minor changes to it. No worries—it's quickly done, as detailed here:

1. In the News project, right-click the project node, select Add, and then click New Item... .
2. Under the Visual C# Items node on the left, select Xamarin.Forms.
3. Select Content Page and name it MainShell.
4. Click Add to create the page.

Excellent! Now, we need to modify the XAML and change the root node to Shell and remove some unnecessary tags.

1. In the News project, open the MainShell.xaml file.
2. Replace the root node and remove the content of the root node so that the file looks like the code in the following snippet:

<?xml version="1.0" encoding="UTF-8"?>
<Shell xmlns="http://xamarin.com/schemas...