Creating my Base Map within Unreal Engine

I created a 31x31 landscape within Unreal Engine to create my base map. I decided to follow the exact layout I had previously created on my birds eye view layout to try and create the image in my mind. Once I had got the desired shape I then started to contemplate specifically what i want the level to like with regard to the texture of the floor. On the map I drew up I wanted to have the floor being sand and grass so now I need to figure out specifically how to achieve this.