Thread: Working with Arrays

I'm having a problem with one part of this assignment, the instruction is this "Add a method transaction which takes two int parameters, daynum and amount. daynum is the day of the month, and amount is an amount of money made or lost for a transaction on that day. (hint: days of the month are numbered starting from 1, arrays arent; think about how to handle this)." this is what I have so far

 public class MonthlyRecord {
//instance variables
    private String month;
    private double[] moneyDaily;
 
//default constructor
    public MonthlyRecord() {
        month = "January";
        moneyDaily = new double[31];
    }
//accessor for monthlyRecord
    public String getMonth() {
        return month;
    }
//mutator for monthlyRecord
    public void setMonth(String v) {
        month = v;
    }
//constructor with parameters from whatever is calling it
    public MonthlyRecord(String b, int x) {
        month = b;
        moneyDaily = new double[x];
    }
 /*Add a method transaction which takes two
  * int parameters, daynum and amount.  
  * daynum is the day of the month, 
  * and amount is an amount of money made or 
  * lost for a transaction on that day*/   
 
 
    public void Transaction(int dayNum, int amount) {
   dayNum = 0;
   amount = 0;

It could just be because my brain feels a lttle fried for some reason, but what am I missing here to ensure this is done correctly? Thx in advance!