It stands for Intel® Hardware Accelerated Execution Manager and it makes Android emulation faster. The items are mostly self-explanatory but Intel® HAXM might be unfamiliar to some developers. Next step in the installation is to select the products to install. Check the 'I agree to license terms' checkbox and make a note of the automatic usage and error reporting request. To start the actual installation process, you must read and accept the Xamarin software license terms. OS X Gatekeeper may show a dialog asking you for a confirmation to open the downloaded application. Once the prerequisites have been met, run the Xamarin Installer by double clicking the Xamarin logo. The latest version of Xcode from the Mac App Store or the Apple Developer Website.The latest iOS SDK from the iOS developer center.To develop Xamarin.iOS applications, the following prerequisites have to be met: Android SDK) on top of Xamarin.Android, Xamarin.iOS and Xamarin Studio. The Xamarin Unified installer takes care of identifying and installing all the required non-Xamarin components (e.g. A few fields need to be filled to download the installer as shown in the picture below. The first step to start Xamarin development on an OS X machine, is to download and install Xamarin Studio Community version from the official website.

Xamarin studio