Concatenate Checkbox Responses in Ecel

I have an excel form with set of 6 check boxes. In VBA I know how to determine if the checkbox is checked or not, what I'm trying to do is reference them so I can concatenate that information into string to output to another cell.

For example if "Check Box 1" is checked I would like to output "Box1" in another cell, if both "Check Box 1" and "Check Box 2" is checked I would like to output "Box1, Box2" in a cell and so forth.

If ActiveSheet.Shapes("Check Box 1").ControlFormat.Value = 1 Then