Pass value and add line to multiline textbox

Hi there,
I'm here to ask again for help since I can't find any solution on the Net coming for help..

The scenario is the following:
In a Userform I have a textbox in which the user enters the data.
Clicking a Command Button I want to pass the inserted data in a destination Multiline Textbox.

What I've done so far:
Setting up the Userform with the controls and try to write the following code.

Private Sub InsertData_Click()
TextBox.Text = Data.Value & vbCrLf
Data.Value = ""
End Sub

Problem:
The values are always overwritten in the same line.

Any hint?
In attachment the dummy worksheet.

thanks in advance!
P.