Beginner C++Programming - Functions?

[Allison2106]

'Write a program that uses three functions:
DisplayInstructions() is a function that takes no arguments and returns no value but simply displays the instructions on what the program does using printf statements.
CalculateAverage() is a function that takes 3 integer arguments and returns the average of them as a floating point number
DisplayAnswer() is a function that takes one floating point number as an argument and displays the value of it.
Your program should start by calling DisplayInstructions(), then it should read the integers after asking the user for them.
It should then call the function CalculateAverage() to find the average of the three numbers.
Finally, it should display the result by calling the function DisplayAnswer().'


I have no idea where to start with this one, could anyone offer me some guidance? I don't understand what it means by 'displaying instructions on what the program does', nor do I get the concept of function call outs. Any help will be appreciated, thank you.