I have Visual Studio 2013 Standard.
I downloaded the CRM SDK from here: http://www.microsoft.com/en-gb/download/details.aspx?id=40321
I go into \SDK\Tools\DeveloperToolkit and click the file: CrmDeveloperToolsVS12_Installer
I get this error: "Visual Studio must be installed before you can install the Microsoft Dynamics CRM Developer Toolkit".
What am I doing wrong?