Need help with finding the surface area and volume for this please thanks I just need step by step help so I can understand it myself

Answer:
144
Step-by-step explanation:
First, do the top and bottom. The top is 2*4*3 or 24, and the bottom is 6*4 or 24.
Now, do the sides. It is a staircase that you can split into 6 2x2 blocks, or 6*4=24. Do the same with the other side to get 24 again.
Now for the front and back. This is 2*4*3 and 6*4 again, or 24 and 24.
Now you have 6 24's so just multiply these and get 144.