Hi Mayank,
For to get a value from a text field, you need know the editText uid. Suppose that your EditText has the uid 'MyText', after the line " 'Shelf Number", you will do something like this:
Dim oText As SAPbouiCOM.EditText = Nothing
oText = CType(oForm.Items.Item("myText").Specific, SAPbouiCOM.EditText)
oUserTable.UserFields.Fields.Item("U_DemoData").Value = oText.Value
Hope it helps!
Regards,
Diego