Note that you're writing pseudocode for this problem, not compilable code. If your instructor has a preferred style for the pseudocode you should use it if possible.
Steps 2-6 contain the basic requirements for the pseudocode.
#2 can be as simple as:
print ("This program will calculate the volume and surface area of a cube...") // Add as much detail as you want
#3:
print ("Please enter the length of a side,")
input s
#4: This is just a tip for writing the pseudocode. Use it if you need to depending on the shape you pick.
#5: Write a couple of lines of pseudocode to calculate the volume and surface area. Then you can print the result:
print ("The volume of the cube is... and the surface area is...")
#6: Include a comment at the beginning of the pseudocode that includes the requested information Maybe something like:
// This program calculates the volume and surface area of a cube.
// Required input: the length of a side of the cube.
// Algorithm: The volume and surface are calculated as follows...
// Output: the calculated volume and surface area.