An objection to a Will is covered under the Surrogate's Court Procedure Act section 1410.  I would go down to the Surrogate's Court and ask them where you can look up the requirements or find a form that would give you the basics that you can copy.  I say this because the Surrogate's Court clerks are generally the nicest around and will guide you without giving legal advice.  Sometimes these forms are pre-printed (like a Blumberg form) and sometimes you just have to set forth the objections clearly and concisely in an affidavit.  Be aware that there is a $150 filing fee in New York to file the form.  Good luck.