For your first Hello World make sure you Development PC is setup correctly. Follow our article How to setup development environment for Windows IoT and VS2015
Then follow this instructions: https://github.com/ms-iot/content/blob/4b650c7c3c0513fd8f24207893d0663daeed68b4/en-US/Samples/HelloWorld.md
Make sure you choose the option for ARM (Rpi2 / Dragon Board)
