You know, the Live DB is not moderated, so, sometimes the materials are not properly created, probably we need a rating system
In my opinion the online documentation is not so bad:https://docs.otoy.com/#rOctaneRender%20Universe
OctaneRender is still young and quite fluid because of its continuous development, so the documentation is not an easy task, but Otoy is working hard to improve also this aspect.
About coustics, first of all, you need to switch to the PMC kernel, since Path Tracing is not really good in this aspect.
Then you need a tiny light source, like the sun or a mesh emitter not greater then 10 cm, otherwise the coustics will be blurred and difficult to be seen.
On the PMC kernel side, you need to know that is not possible to reduce the GI Clamp value to speed up the render, because the caustics will be cutted.
The Parallelism value must be set to 1 and you can slightly increase or decrease the Coustic blur value for speeding up a bit the calculation, in general , not greater then 0.025.
A value of 0 gives sharper caustics.
I hope that this is enough for you for starting to work with caustics, let us know if you have more questions