Simple edge erode or edge smoother via blueprint

Can 1 kind soul guide me on how to do a simple way to take the harsh key outline off the alpha. I’ve spent the last 2 weeks checking everyday from the ue4 vp groups to the discords…Either no one will answer or they just dont know how… In AE its so simple just to shrink the key and smooth the edges… in ue4 all the videos i find its like a 50 step blueprint that end the end does not work for me… Any 1 can please help with this super simple problem?