Pay more attention to the accuracy of your "getting started" web pages
I started here:http://dev.office.com/getting-started/addins . I downloaded and installed VS 2015 Community edition. I got to here "3.In the New Project dialog, choose Templates > Visual C# > Office/SharePoint > Apps." But there is no such option. The "getting started" web page has no feedback option, which is why I am posting here. I have since discovered that what I need is to get and run the Web Platform Installer at http://aka.ms/officedevtoolsforvs2015 . That does appear to install the necessary stuff. There are enough barriers for people trying to get started - IMO the easier you can make the process, the more people are likely actually not to give up.
Thank you so much for reporting this to us! We really appreciate it! We’ve reviewed these pages and fixed any inaccuracies.
Office Extensibility Team
Peter Jamieson commented