I'm studying a lot in these last weeks. My goal is learn how to use Houdini and the Niagara system in Unreal. Is been pretty fun.
For the splatter effects, I was studying this tutorial of Andreas Glad (https://www.artstation.com/partikel). It's a little out of date and you'll need to research to discover how to make the effect work with the new nodes, but I strongly recommend to watch:
https://www.sidefx.com/tutorials/vat-paintsplat-houdini-for-games/?collection=32