Mono for Android requires Visual Studio Professional or better, and does not support Visual Studio Express. This is because the express edition does not support plugins.
First, download the installer via here:
Run the installer to initiate the installation. The process is quite straightforward:
Android SDK has several dependencies on Java JDK (Java Development Kit) which is actually a bundle of software (such as compilers, debuggers, libraries, etc.) that is needed to develop Java based applications. Java Runtime Environment (JRE) is not enough for Mono for Android.
Close the window to complete the installation. You can also view the installation log.
The next step is telling Visual Studio where to find the components that were just installed.
Go to: Tools > Options > Mono for Android > Settings
In Windows 7, browse to the following directory to locate the Android SDK path:
Click on the OK button and restart your Visual Studio for the change to take effect.
You can also check the “Use default device” checkbox and click on the browse button in order to view the available AVDs (Android Virtual Devices) that were installed by the Mono for Android installer. The installer, by default, creates AVDs for each of the Android versions that were registered by itself.
The new virtual devices will be listed along with the existing ones if you already have any.
Another way of viewing these AVDs is visiting the Android SDK Manager. Go to the Android SDK directory, and click on the SDK Manager.exe:
If you want to create a new AVD, make sure that you have the SDK for the Android version installed (in Android SDK Manager) and click on the New button to proceed.
At this point, you should have everything ready to go in order to create an Android application using Mono for Android.