visual basic 2005 mortgage calculator

I need to write a mortgage calculator so that it displays a list of the total interest balance, monlthy payments, etc.  I dont want any straight answers, but any resources that will teach me how to do it.  I know you don't mean to answer homework questions, but I am new to this and simply don't know how to do it. and unfortunately this school does function to actually teach.  Therefore, if anyone knows of any valuable resouces that explain more complicated processes, please let me know.

Public Class Form1
 
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Button1.Enabled = False
    End Sub
 
    Private Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click
 
        Dim Principle As Integer
        Dim Rate As Integer
        Dim Term As Integer
 
        Dim MonthlyPayment As Integer
 
        Dim mRate As Double
        Dim mTerm As Double
 
        Principle = Convert.ToString(Amount.Text)
        Rate = Convert.ToString(iRate.Text)
        Term = Convert.ToString(Years.Text)
 
        mRate = Rate / (12 * 100)
        mTerm = Term * 12
        MonthlyPayment = (Principle * mRate) / (1 - ((1 + mRate) ^ -mTerm))
 
        Label5.Text = MonthlyPayment.ToString("C")
 
 
 
 
 
 
    End Sub
 
 
 
 
    Private Sub TextBox1_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Amount.TextChanged
        If Amount.Text.Length > 0 And iRate.Text.Length > 0 And Years.Text.Length > 0 Then
            Button1.Enabled = True
        Else
            Button1.Enabled = False
 
 
        End If
 
    End Sub
 
 
 
    Private Sub TextBox2_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles iRate.TextChanged
        If Amount.Text.Length > 0 And iRate.Text.Length > 0 And Years.Text.Length > 0 Then
            Button1.Enabled = True
        Else
            Button1.Enabled = False
 
 
        End If
    End Sub
 
    Private Sub TextBox3_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Years.TextChanged
        If Amount.Text.Length > 0 And iRate.Text.Length > 0 And Years.Text.Length > 0 Then
            Button1.Enabled = True
        Else
            Button1.Enabled = False
 
 
        End If
    End Sub
 
 
    Private Sub ListBox1_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ListBox1.SelectedIndexChanged
 
        Dim Principle As Integer
        Dim Rate As Integer
        Dim Term As Integer
 
        Dim MonthlyPayment As Integer
 
        Dim mRate As Double
        Dim mTerm As Double
        Dim iPrinciple As Double
        Dim TotalBalance As Double
        Dim rbalance As Double
 
 
        Principle = Convert.ToString(Amount.Text)
        Rate = Convert.ToString(iRate.Text)
        Term = Convert.ToString(Years.Text)
        Principle = Convert.ToString(Amount.Text)
        Rate = Convert.ToString(iRate.Text)
        Term = Convert.ToString(Years.Text)
 
        mRate = Rate / (12 * 100)
        mTerm = Term * 12
        MonthlyPayment = (Principle * mRate) / (1 - ((1 + mRate) ^ -mTerm))
 
 
 
    End Sub
End Class

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