how to use formula b=p (1+r)^n, to calculate annual interests for a savings account in visual basic project

Question

This is my code so far>>>>>>>>>>>>>>

Option Explicit On
Option Strict On
Option Infer Off

Public Class MainForm

Private Function FV(ByVal p As Single, n As Integer) As Double

Const annuinterestrate1 As Double = 0.02
Const annuinterestrate2 As Double = 0.03
Const annuinterestrate3 As Double = 0.04

Dim deposit As Double
Dim withdrawals As Double
Dim r As Single

Dim initialbalance As Double
Dim balance As Double

balance = initialbalance

initialbalance = p * (1 + r) ^ n

Dim interest As Double = Convert.ToDouble(balance * annuinterestrate1 / 12)
balance += Convert.ToDouble(interest)

End Function

Private Function b() As Double
Throw New NotImplementedException()
End Function

Private Sub CalcButton_Click(sender As Object, e As EventArgs) Handles CalcButton.Click

End Sub
End Class