1st you're going to want to divide the figures into smaller parts. I deviated them and got the measurements 2W, 1L, and 2H. The formula for rectangular prisms is LxWxH and I got 4.
Now we need to use the same formula for the other figure.
4L, 2W, and 1H.
Multiple them all and we get 8
Now we take the Volume of both the figures and add them together 8+4 = 12
So, the volume of the composite figure is 12