Particle SubUV Help

Hey everyone, I created and explosion thats 48 frames in After effects, I used “Contact Sheet II” in Photoshop to compile all the images into one texture sheet a 2048 x 2048 targa. Im having issues getting that TGA setup in UE4 to be made into a SubUV Movie clip for use with an emitter. Any tutorials, walkthroughs or suggestions out there?

And watch this if you want to learn more about Cascade. http://www.youtube.com/watch?v=GCfmwSonCBw&list=UUA-sP_G8gDY0V9YOOpK7V1g

He uses UDK but majority of the settings still apply to UE4.