Draw a right rectangular prism. Draw it so one face is pretty much the way you would see it if it was real. The other two faces you can see have a slant to them.
Label the face you can see as x and y. Name any of the slanted lines as z. Put cm for centimeters behind the letters.
Volume = x*y*z the units here are cm^3 Why because you are multiplying cm*cm*cm together.
The surface area is a whole different ball game. you have 2 surfaces who have areas of x*y There's one in front of you and one you cannot see You have a top and a bottom that is y*z each that's 2y*z
You have two surfaces that are x*z each and that's 2x*z
The total surface area = 2xy + 2xz + 2yz The units here are cm*cm or cm^2