1: Setting up caustics in your scene is as simple as adding the material function MF_UIWSCaustics to any of your materials that you wish to be affected by caustic lighting.
ColorCausticContribution(S) is basically a multiplier for how bright the interactive caustics will be on any given material. Values between 1 and 3 are typical.
You should connect your shader’s base color to the function InColor(V3) input
If you would like water ripples to affect your foliage World Position Offset, simply route your foliage materials existing WPO through the caustics material function and your foliage will sway in the waves.