OpenGL simple program

Hello guys! I am fairly new to OpenGL and Oculus VR. I am trying to build a cubemap for the rift. I already have a program running in OpenGL in C++ but I don't understand how to render the cubemap into the oculus rift. I took a look at the tiny room gl program given by the sdk but I don't entirely understand how the rendering happens. Has anyone done a tutorial or a project where you focus on practicing just the rendering? Can anyone help me understand how to display something into the oculus?