Please provide layman's terms

Could you give a brief explanation to the areas where you see // ???  Thank you and here is my program.

 public static void main(String[] args)

    {

          DecimalFormat twoDigits = new DecimalFormat("$###,###.00");

         
        double mortgage = 200000.00;
        double[][] yearsYearlyRate =  //Multiplies term by interest rate

       
        {
            { 7, 15, 30 },          
            { 5.35, 5.5, 5.75 }
        };

       
        double[][] monthsMonthlyRt =

        {
            {
                 yearsYearlyRate[0][0] * 12, yearsYearlyRate[0][1] * 12,
              yearsYearlyRate[0][2] * 12  
            },
            {
             
                    yearsYearlyRate[1][0] / 1200, yearsYearlyRate[1][1] / 1200,
                    yearsYearlyRate[1][2] / 1200
            }
        };


       
        for (int i = 0; i < 3; i++) // brief descriotion please of what this means

        {

            // ??? Please help here
            double payment = calPayment(monthsMonthlyRt[1][i], monthsMonthlyRt[0][i], mortgage);

           

            System.out.println("\nMortgage Amount \tTerm \t\tRate \t\tMonthly Payment");
            System.out.println("$200,000 \t\t" + yearsYearlyRate[0][i] + " years\t"
            + yearsYearlyRate[1][i] + "%\t\t" + twoDigits.format(payment));


            System.out.println("\nPayment # \tMonthly Interest Paid \t\tRemaining Loan Balance");

           
            interestBalanceList(mortgage, monthsMonthlyRt[1][i], monthsMonthlyRt[0][i], payment);

        }

    }

    // I totally do not understand what this entire double tmp or param thing means.  Please help !!!
    public static double calPayment(double param1, double param2, double mortgage) {


              double tmp = 1 + ( param1 ) ;
              for ( int i = 1 ; i < param2 ; i++)
              tmp = tmp * ( 1 + param1 ) ;
              double monthlyPayment = mortgage * tmp * param1 / ( tmp - 1 ) ;

     
      // double monthlyPayment = (param1 + param2 / (Math.pow((1 + param1), param2) - 1)) * mortgage;

             return monthlyPayment;
    }

   
    public static void interestBalanceList(double mortgage, double param1, double param2,
    double payment)

            {

       
             for (int i = 1; i < (param2 + 1); i++)  // Provide brief description please

        {


            System.out.println("Press 'ENTER' to view the loan amortization.");

            try

            {
                System.in.read();    
            }   catch (Exception e)  // what will the catch portion do ?????


            {

            }

            // Calculate the Monthly Interest of the Loan Balance
            double monthlyInterest = mortgage * param1;

            // Calculate the Remaining Loan Balance
            double loanRemaining = mortgage - (payment - monthlyInterest);

            // Set the value of Mortgage Amount to the Value of the Remaining Loan Balance
            mortgage = loanRemaining;

            // Format the Monthly Interest Amount into U.S. Currency
            NumberFormat n = NumberFormat.getCurrencyInstance(Locale.US);
            String str = n.format(monthlyInterest);

            // Format the Remaining Loan Balance into U.S. Currency
            NumberFormat num = NumberFormat.getCurrencyInstance(Locale.US);
            String string = num.format(loanRemaining);

         

            System.out.println("\n " + i + "\t\t\t" + str + "\t\t\t" + string);  // Please explain the string ???????

        }
    }  // Also, I would like to make the program pause after showing 12 payments on the screen so
       // how would I go about doing this ?????
}