Trust me, it's really easy!
break apart the shape (In 3D, I assume.) there should be 6 breaks apart. The top, bottom, and four sides. After you find the area, (Base x Base x Height for the 4 sides, and Side x Side for the top and the bottom of the figure.) Then you add all of them up, and there's the surface area! If you need more help, message me, I'd be glad to help.