Adding text to cell from textbox based on combobox column in Excel VBA?

Question

I want to write something to cells from based on combobox selection. For example; i wrote to textbox "Hello" and i choosed "Messages" selection from combobox. After push the "Register" button, code have to write "Hello" to column, which's column title is "Messages". And my combobox choices are have just first row, they are my table's titles. After someone choose something from combobox and write someting to textbox, someone have to push to button for register. That's totally what i want to make. Please explain in detail, because i'm beginner on Excel VBA, Thanks for helping to me.

I added first row values to combobox with that code;

Private Sub UserForm_Activate()
  Dim vList As Variant

    For Each vList In [Machines]
        Me.ComboBox1.AddItem vList
    Next
    
End Sub