Working with random integers

Here is the assignment: For this program, there are two "parts". The first part will run the trials and determine how many caps each trial opens before finding a winning cap. Every trial (person) will be a winner. The number of caps opened by each trial is written to the file. (The output file should contain only integers). (This is where you will use nested loops...a for and a while...not two for's)

The second part of the program will read in the values and calculate the average. The average should be between 4.5 and 5.5 since there is a 1 in 5 chance of winning.

I know I have many mistakes, I want someone to tell me where to start. I do not know much about java.

My code:

  int randNum = 0; 
  Random randNumList = new Random(); 

  int counter = 0;
  Scanner in = new Scanner(System.in);
  System.out.println("How many trials will there be?");
  int trials = in.nextInt();

  int winner = 0;

  PrintWriter outFile = new PrintWriter (new File("cap.txt")); 
  //run trials
  for (int loop = 1; loop <= trials; loop++)    
  {  
    //select random number until 5 is selected
    randNum = randNumList.nextInt(6);
    for (randNum = randNumList.nextInt(6); randNum == 5; randNum++)
    { 
      randNum = randNumList.nextInt(6);
      counter++;
    }

    outFile.println(loop + " " + randNum);
  }   


  outFile.close ( );    //close the file when finished 

  String token = " ";
  Scanner inFile = new Scanner(new File("cap.txt")); 

  while (inFile.hasNext())
  {      
       token = inFile.next();
       if(token.equals("5"))
         winner++;  
  }

  double average = winner/counter;
  System.out.println("The average number is " + average);