(SM5) Meterial using deferred decal domain

I’m trying to make a translucent decal I pulled off of google. It’s just blood splatter. I load it into Unreal and make a material. When I change the material domain to Deferred Decal. I get this error: (SM5)Material using deferred decal domain BlendModel Translucent.(this saves performance)

On a side note: The PNG of the blood splatter background is white. Does it have to be black for the alpha channel?
I can’t seem to find the right settings. I’ve tried several youtube tutorials and can’t find the basic settings.

What are the best settings for a decal:
Material Domain> Deferred Decal
Blend mode?
decal blend mode?