Need help with this EOF based and running total loop?

[KoolKat]

Hi, here are the instructions for the project I have to do:
http://pastebin.com/n7wyyDWA

I'm new to java and I'm trying my best to figure this out on my own, but after about 6 hours of trying, my brain is a bit fried. I'd like to know what I'm doing wrong and what I need to add.
Here is what I have so far:

import java.util.*;
public class p5
{
  static Scanner kb = new Scanner(System.in);
  public static void main (String[] args)    
  {
// number entered and the running total
    int inputNum, sum = 0;
// count of valid and invalid numbers seen
    int numValid = 0, numInvalid = 0;
    double average;
    
    System.out.println("Enter a positive value (Ctrl-D to quit): ");
    while ( kb.hasNext() )
    {
      inputNum = kb.nextInt();
      if ( inputNum < 0 )
        System.out.println("The number " + inputNum + " is invalid.");
      
      
      else
        
        System.out.println("Enter a positive value (Ctrl-D to quit): ");
    }                    
    // System.out.println("The sum of the valid numbers was " + sum + " and the average was " + average + ".");
  }
}

I know I need the valid and invalid numbers to add up and create a sum and average, but I have no idea how to do that.

If anyone could shed some light, I'd really like to learn about what I'm doing wrong/right and not just be given the answer. I don't want to seem like I'm cheating, I just need some guidance.

Thanks!