Trying to understand how to access controls on Tabs done at runtime - tabcontrol

Question

newbie here; Im trying to migrate my VB program to run in Tabs. so far I have been experimenting with creating Tabs at runtime with added controls. I figured out that I can create tabs and add controls at either FormLoad() or by an execute Button. However, I can not access those controls once the Tab is created. I can not get any info from a combo, text box either outside the created Tab. Here is a simple program that I manage to put together:
Public Class Form1
Inherits Form
Private tabControl1 As TabControl
Private tabPage1 As TabPage
Private tabPage2 As TabPage
Dim nm As String
Private Sub MyTabs()
Me.tabControl1 = New TabControl()
Me.tabPage1 = New TabPage()
Me.tabPage2 = New TabPage()
Dim txtBox1 As New Windows.Forms.TextBox With {.Parent = tabPage1}
Dim CalcButton As New Windows.Forms.Button With {.Parent = tabPage1}
CalcButton.Location = New Point(1572, 150)
CalcButton.Size = New Point(100, 50)
CalcButton.Text = "CALCULATE"
txtBox1.Location = New Point(1572, 258)
txtBox1.Size = New Point(70, 22)
txtBox1.Name = "Loc_num"
txtBox1.Text = "1"
nm = txtBox1.Text
Me.tabControl1.Controls.AddRange(New Control() {Me.tabPage1, Me.tabPage2})
Me.tabControl1.Padding = New Point(15, 10)
Me.tabControl1.Location = New Point(35, 25)
Me.tabControl1.Size = New Size(1800, 750)
' Selects tabPage1 using SelectedTab
Me.tabControl1.SelectedTab = tabPage1
Me.tabPage1.Text = "tabPage1"
Me.tabPage2.Text = "tabPage2"
Me.Size = New Size(2000, 900)
Me.Controls.AddRange(New Control() {Me.tabControl1})
AddHandler CalcButton.Click, AddressOf CalcButton_Click
End Sub
Private Sub CalcButton_Click()
Dim xx As Integer
Me.tabControl1.SelectedTab = tabPage1
xx = Convert.ToInt32(nm) ' IT KEEPS SHOWING A 1, EVENTHOU I CHANGED IT TO 4 WHEN FORM LOADS
MessageBox.Show(nm)
End Sub
Public Sub New()
MyTabs()
End Sub
Public Sub Main()
Application.Run(New Form1())
End Sub
End Class
Im not sure if its possible to continue of this path
Thanks for any help or comment