This form is for general instructions that apply to all corporation tax forms. It includes a variety of topics about how to fill out your form.A. Account Information. The following answers to frequently asked questions may help you decide whether you should appeal your property's assessment and will guide you on how to do it. Closely held corporations must test whether the personal holding company tax applies and what measures to take to avoid it. Nassau has a strong commitment to adhere to the suitability guidelines set forth in the NAIC. Fill out FFE and datum. Finished Floor Elevation (FFE):.