If you want to run the iOS app in the simulator on your window machine, you need to:
1- Download the Remoted iOS Simulator from the following address:
2- In Visual studio open Xamarin mac agent and connect to the mac you already made ready for Xamarin development.
3- In "Solution Platforms" drop-down list in Visual Studio select iPhoneSimulator and from the list of devices select the type of the device you need to test the app on.
4- Run the app with debugging. It will open a simulator windows and run the app in it.
* If the version of Xamarin installed on your machine is different from the version installed on the Mac you will face problems doing this. Make sure the versions are right
* Do not close the simulator windows every time that you stop debugging.