I would suggest that you contact the Surrogate's office in the county where your mother passed away. The Surrogate is the part of the Court system that deals with estates and probate. The Surrogate's offices usually are very helpful, and will be able to assist you in obtaining information, getting forms, etc. Obviously, a lawyer can help you do this directly.
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I co-authored a book on precisely this topic "Guiding Those Left Behind in New Jersey - Settling the Affairs of Your Loved One" While I doubt its available in your local bookstore it can still be ordered from the publisher. There is a link to the publisher in my Avvo profile.
Additionally, many attorneys will offer a free initial consultation to help you determine if you need any ongoing legal help with the estate or if you can handle it on your own.
Very truly yours,
NOTE: This answer was prepared for educational purposes only. By using this site you understand and agree that there is no attorney client relationship or confidentiality between you and the attorney responding. This site should not be used as a substitute for competent legal advice from a licensed attorney that practices in the subject area in your jurisdiction and with whom you have an attorney client relationship. The law changes frequently and varies from jurisdiction to jurisdiction. The information and materials provided are general in nature, and may not apply to a specific factual or legal circumstance described in the question or omitted from the question.