View > Others Windows > Xamarin.Forms Previewer
You will saw the Error as below
Step 1: Android Application preview, be sure that you have the latest Java 1.8 x64 installed from here
http://www.oracle.com/technetwork/java/javase/downloads/jre8-downloads-2133155.html
Step 2: install java 1.8 x64 and change to Android JDK path from Visual studio
Goto Tools Menu> Select Options > Xamarin> Android Setting > change Java Development kit location