There are two modes, 2D mode and 3D mode.
To select a mode you just import a different file.
First you must install the module
npm install rjsengine
You use the import key word to import either the 2D or 3D Mode.
That will give you access to all of the classes you need.
View the wiki on how to use the engine here: https://github.com/ryandw11/JSEngine/wiki