There are 3 main parts of Virtual Reality in general.
Native VR App
1) Game Engine - Unity
You have to learn C# and Javascript.
If you are a newbie of programming, DOM Scripting: Web Design with JavaScript and the Document Object Model and Eloquent JavaScript would be a good start.
If you already have programming experience, JavaScript: The Good Parts is a best choice.
For Unity, you may follow Roll-a-ball tutorial offered by Unity3D official website. Then, Oculus Developer Center Documentation may give you more detail.
2) The tutorials above are all related to VR output device, if you are interested in VR input device, such as UI/UX of VR, Leap Motion (Oculus touch or HTC Vive) is a good choice.
3) Besides of programming background, you also need some mathematical knowledge, Essential Mathematics for Games and Interactive Application：A Programmer’s Guide，Second Edition are recommended.
VR Movies
VR Movies is another part of VR, you may Google “VR camera rig” for more information if you are interested.
VR Web
You need learn three.js at first. three.js is a cross-browser JavaScript library/API used to create and display animated 3D computer graphics in a web browser. The source code is hosted in a repository on GitHub.
Then you can follow borismus/webvr-boilerplate project on Github to build a sample VR website. Remember you should use Chromium or Mozilla nightly to test you site, take webvr.info for reference. In addition, Hello-Cannon.js! is another interesting project.
Let us wander in the sea of VR.
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