User manual (updated 03.02.2017)
The standalone version of VREX simply starts by double-clicking on the executable file. When using the source version of VREX, you first need to download and install Unity. After launcing the engine, you will be greeted with a splash screen. There you can locate the project folder and open it in Unity.
When inside the editor, launching VREX requires two clicks. First make sure the Game view is set to "maximize on play" to make the most from your screen space. Next hit the play button to start constructing and running the experiments. Be sure to have the "MainMenu" scene open (located from the asset browser at the bottom of the screen).
While running VREX, you can pause the program and tweak various settings of the game components. This allows you for example to quickly try out different movement speeds until you find the suitable value.