Research the laws in your state. Wills are a matter of state law and the rules vary between states. In some states, wills for estates under a statutory amount do not need to go through probate. In other states, the executor must carry out certain duties immediately.
File the appropriate probate petition with the court clerk in the county in which the deceased lived. The form varies from state to state, but is often available from an online legal document service. You should receive notice of a hearing back from the court.
Go to probate court at the designated time with proof of your identity as the person named as the executor in the will. Appropriate proof is usually a government-issued photo ID.
Ask the court to confirm you as the executor of the will. If challenged, you may need to prove that you are fit to act as an executor. In most states, this means you need to prove to the court's satisfaction that you are at or above the age of majority, competent and financially responsible.