Create the textbox on your form, and then create code in the OnClick event of your button.
You will need to get the values from your fields and combine them into a single output for the box. I assume there are a number of ways this can be done, but the simplest to understand would probably be to create a temp string variable to hold all the results, then collect the values from all the selections into the temp variable. Once you have all of them, set the textbox value equal to your temp variable.
Code:
Dim sTmp As String
sTmp = Me.cboSize.Value
sTmp = sTmp & vbCrLf & Me.cboBread.Value
...
Me.txtOutput.Value = sTmp
(vbCrLf is a Carriage Return/Line Feed)
The object names I used do not match your sample (which used default names like "Combo14" making it a lot harder to reference them logically when writing code) but it should give you some ideas to get moving in the right direction.