Form Workflow will create columns as soon as you start collecting Form responses. The first column will be the Status column.
It is important that you do not change the name of this column (or any other column created by Form Workflow) as the add-on will "read" the content here to complete the other columns that will be created upon 1st and/or 2nd reviewer submissions.
If you change the name of any column header Form Workflow will create a new column header and ignore the column with the changed name. All Status validation will take place under the new column header.