This short article cannot complete the steps because you need an account in Xamarin. A lot of the developers will ask why after buying Visual Studio and yet need to pay to create iOS. I got no answer for that.
Probably you can use the Ionic for IOS as well. For more information refer to https://chanmingman.wordpress.com/2015/05/11/ionic-framework-for-mobile-development-using-visual-studio-2015/.
Once you start Visual Studio 2015 RC go to File -> New -> Project…
Under Visual C# Template you should be able to see iOS, choose the iPhone.
Once you click OK then the Connect to a Xamarin iOS Build Host dialog appeared.
I stuck when I click Configure.
Somehow you can click Close to continue. You can see the C# code and so.
Unfortunately once you click the Run. If you do not have a Xamarin account then you will not be able to continue.