Hello! Anyone can help me about how i can use auto material and terrain paint at the same time?

Im new on UE4 just started to use it a few days ago. I created my auto material (which i use on the map now) and i also have a paint tool. How can i use both at the same time? I would like to use the auto mat for the base of my map but i would like to paint small areas to different materials(like painting pebbles to the streams,ocean or similar things).