If you don't have existing code, then just use the Ninja Coder Visual Studio Extension for MVVMCross. If you have existing code already (ie: running an Xamarin android that you want to port to MvvmCross, then follow these steps:

Creating New MvvmCross Project

Setting up the Core Project

• Create a new PCL
• select .NET Framework 4.5, Windows 8, Windows Phone Silverlight 8, Windows Phone 8.1, Xamarin.Android and Xamarin.iOS - this will ensure that the PCL is in Profile259.
• Install the nuget package into this Core Project:

Install-Package MvvmCross.HotTuna.MvvmCrossLibraries

• Create an App.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Cirrious.CrossCore.Plugins;

namespace Something.Core
{
    public class App : Cirrious.MvvmCross.ViewModels.MvxApplication
    {
        public override void LoadPlugins(IMvxPluginManager pluginManager)
        {
            base.LoadPlugins(pluginManager);
        }

        public override void Initialize()
        {
            RegisterAppStart<ViewModels.SomeStartingViewModel>();
        }
    }
}

Creating New Android Project

• Open your Xamarin Android projct

Install-Package MvvmCross.HotTuna.MvvmCrossLibraries

• Download the Android Resource file here

• Add the Android Resource file to the /Resources/Values folder

• Set it's BuildAction set to AndroidResource

• Create a new Setup.cs file

using Android.Content;
using Cirrious.MvvmCross.Droid.Platform;
using Cirrious.MvvmCross.ViewModels;
using Something.Core;

namespace Something.Droid
{
    public class Setup : MvxAndroidSetup
    {
        public Setup(Context applicationContext)
            : base(applicationContext)
        {
        }

        protected override IMvxApplication CreateApp()
        {
            return new App();
        }
    }
}

Unit Test Project

Install-Package MvvmCross.HotTuna.MvvmCrossLibraries

Install-Package MvvmCross.HotTuna.Tests -Version 3.2.1