To find the surface area of ANY prism you need to find the area of individual shape first.
To find 2 faces of the prism, you will need to do bxh. As there is 2 of the same rectangle , you need to multiply it by 2. Therefore, the first number you need is 16m squared.
To find the next part of the prism, you will need to do 2m x 3m which is 6m. You need the area so 6m squared (The units are important). There are also 2 of these, so multiply it by 2 to get 12m squared.
For the final part of the prism, you will need to do 4m x 3m which is 12m squared. There are 2 of these so the it is 24m squared.
Finally, you will need to add all these figures up.
16m squared + 12m squared + 24m squared = 52m squared