I always forget how and where to get the Revit Add-In Manager, that “External tools” ribbon in your Add-Ins tab. Essential tool if you want to debug your Add-In without restarting Revit each time. It is as simple as it follows:

• download and install the Revit SDK you need (or see below on how to get it from you installation package)
• in the new folder C:\Revit 2013 SDK\Add-In Manager (or similar) you will find the file Add-In Manager for Autodesk Revit 2013.msi, now just install it N.B.

The SDK is included in every Revit product.  There are two ways to install the Revit SDK:

• From the main page of the Revit installer, click “Install Tools and Utilities” and choose “Revit Software Development Kit”.
• Alternatively, you can also find the SDK in the extraction folder, under: *\support\SDK\RevitSDK.exe*