Determine your standing to open probate. If you are named executor -- termed personal representative in some states -- your standing is unquestionable in every jurisdiction. However, any person who has a pecuniary interest in the last will and testament can file the probate petition. If you inherit under the will, you have standing to file. Close family ties alone do not confer standing.
Review the probate statutes in the jurisdiction in which the testator resided. Many courts have self-help pages on the Internet; alternatively, visit the probate court and request a probate packet of forms like the one for Los Angeles Superior Court, linked in Resources. Read the instructions to determine the contents of the initial filing. Generally the first form is entitle "Petition for Probate." Many courts use simple, informal procedures for small estates, a practice that cuts down the cost and complexity of probating a will.
Open the probate process by filing a copy of the death certificate, the original will and the initial probate document with the clerk of the probate court. If the will names you executor, file appropriate documents to grant letters testamentary authorizing you to administer the estate. Some states have adopted the Uniform Probate Code. In these states the executor must specify in the initial filing whether to proceed with formal or informal probate. The former requires more court involvement and works best for complicated estates or disputed wills.
Attend a hearing to establish the testator's death and place of residency if you select a formal probate proceeding or your jurisdiction otherwise requires. The court also decides whether the will was executed in compliance with statutory requirements including the competency of the testator at the time the will was made. Generally, attesting witnesses -- present at the time the executor signed the will -- affirm those facts. The number of attesting witnesses varies among jurisdictions but, for a prepared will, every state requires at least two adult witnesses. If the court determines that the will was improperly executed, it declares the will void, and the property of the deceased passes to blood relatives according to intestate succession. If the will passes muster, the probate process continues.