adding note, seeing if I have the relative path done correctly

docs/getting-started.md

@@ -19,6 +19,7 @@ localization_priority: Priority
 
 The Open XML SDK 2.5 for Office simplifies the task of manipulating Open XML packages and the underlying Open XML schema elements within a package. The classes in the Open XML SDK 2.5 encapsulate many common tasks that developers perform on Open XML packages, so that you can perform complex operations with just a few lines of code.
 
+[!include[Addins note](../includes/addinsnote.md)]
 
 ------------------------------------------------------------
 ## Using the Classes in the Open XML SDK

docs/includes/addinsnote.md

@@ -0,0 +1,2 @@
+> [!NOTE]
+> Interested in developing solutions that extend the Office experience across [multiple platforms](https://dev.office.com/add-in-availability)? Check out the new [Office Add-ins model](https://dev.office.com/docs/add-ins/overview/office-add-ins). Office Add-ins have a small footprint compared to VSTO Add-ins and solutions, and you can build them by using almost any web programming technology, such as HTML5, JavaScript, CSS3, and XML.