How to save properties from viewmodel?

See more:

C#

XAML

Win10

Currently i'm experimenting with a WinUI3 project from the TemplateStudio and its the first time with MVVM.

I have some textboxes:

<TextBox x:Uid="Settings_Smtp_ServerBox" Text="{x:Bind ViewModel.SmtpServer}" />

Inside the ViewModel i have some properties defined, where the textboxes bound to:

public string SmtpServer
	{
		get => _smtp_server;
		set => SetProperty(ref _smtp_server, value);
	}

The mentioned project has a delivered local settings service what provides that method:

public class LocalSettingsServicePackaged : ILocalSettingsService
{
    public async Task SaveSettingAsync<T>(string key, T value)
    {
        ApplicationData.Current.LocalSettings.Values[key] = await Json.StringifyAsync(value);
    }
}

How do i save the contents of the properties?

What I have tried:

I read the documentation on TemplateStudio/setting-storage.md at main · microsoft/TemplateStudio · GitHub[^]
but the saving process isn't documented.