You need a browser that implements WebGL 2. WebGL 2 is supported by all major browser vendors with the exception of Microsoft Internet Explorer:

• Firefox 51 or above
• Google Chrome 56 or above
• Chrome for Android 64 or above 

An updated list of WebGL-enabled browsers can be found here: http://www.khronos.org/webgl/wiki/Getting_a_WebGL_Implementation.

You also need a source code editor that recognizes and highlights JavaScript syntax.

And you need a web server, such as Apache, Lighttpd, or Python, to load remote assets.