The first step to finding the Surface Area was done well and was right but you got confused when trying to add the area of each shape
There is 3 Rectangles and 2 Traingles.
Let's start with the area of the triangles. 1/2bh is the formula for finding area of Traingles. 1/2(4)(6) = 12. We have two Traingles so that would be 24.
Now we have three rectangles with different lengths we need to calculate.
Rectangle 1 = 12 * 8 = 96
Rectangle 2 = 12 * 6 = 72
Rectangle 3 = 12* 4 = 48
24+96+72+48 = 240.
So, the surface area of the rectangular prisim is 240
