how do I contest a will

If the will has already been probated and an executor name, you will have to file a complaint in the chancery division stating the basis for your challenge to the will and the relief that you want.  For example, if you think the person who wrote the will wasn't capable of doing a will at the time it was written, or if you think someone forced the person to write the will a certain way, then you challenge the capacity of the person writing the will or claim undue influence.  If the will has not been probated, you can file a caveat to prevent probate at the county surrogate's office.