VBA Userform Dependent Combobox

Okay, I have put together a table as an example of what I will be working with. What I would like ideally is:

• Each of the column headers to form an option in Combobox 1 (More will be added)

• Each of the values in the cells under the Headers to represent dependent options in Combobox 2 (these will also change, so need to comboboxes to change accordingly)

• Also, Instead of populating the existing comboboxes in the code with the “AddItem” command, I would like to reference the relevant column on the “Data Input” sheet.

I have included a small piece of existing code to give some idea of where I am at and how I have got there.
What I really need now is the code to do the above, an explanation of what the code is doing would be great – and crucially, how to insert the new code into the existing code so it works!
I hope that has clarified?

Private Sub UserForm_Initialize()				
				
        Application.Visible = False				
        				
        txtCustomer.Value = ""				
				
        txtDetails.Value = ""				
        				
        txtResDetails = ""				
        				
        txtDate.Value = Format(Date, "dd/mm/yyyy")				
        				
        txtTime.Value = Format(Time, "hh:mm")				
        				
With cboOperator				
				
.AddItem "Operator 1"				
				
        .AddItem "Operator 2"				
				
        .AddItem "Operator 3"				
				
        .AddItem "Operator 4"				
				
        .AddItem "Operator 5				
        				
 End With				
				
    cboOperator.Value = ""				
    				
With cboIssue				
				
.AddItem "Missing"				
				
        .AddItem "Quality"				
				
        .AddItem "Short Delivered"				
				
        .AddItem "Damaged"				
				
        .AddItem "Late"				
				
 End With				
				
    cboIssue.Value = ""				
    				
End Sub				
				
Private Sub cmdExit_Click()				
    				
    Unload Me				
    Application.Quit				
				
End Sub				
				
				
Private Sub cmdClear_Click()				
				
    Call UserForm_Initialize				
    				
End Sub				
				
Private Sub cmdUnlock_Click()				
				
If Me.txtPassword.Value = "password" Then				
				
Unload Me				
				
Application.Visible = True				
				
Else				
				
Me.Hide				
				
Retry = MsgBox("The password is incorrect. Do you wish to try again?", vbYesNo, "Retry?")				
				
Select Case Retry				
				
Case Is = vbYes				
				
Me.txtPassword.Value = ""				
				
Me.txtPassword.SetFocus				
				
Me.Show				
				
Case Is = vbNo				
				
Unload Me				
				
End Select				
				
End If				
				
End Sub