Hello!
I just fixed the Discord link, thanks for letting me know! :D
In the .yyz project there's an example specifically about Displacemaps, could you take a look? See: "objPPFX_09_Displacemaps"
Basically, you will use the "PPFX_NormalmapRenderer". This constructor aims to draw normal map objects on its internal surface, and for this, it uses the default parent object "__ppf_objNormalEffect" (localized inside PPFX's folder), which has raindrops as its child, which you can create to generate the drops on the screen.
I hope this helps :)