I have been named successor trustee. What do I do first?

There is a sequence, it starts sooner than most people are told, and the first ninety days decide the next three years.

Someone has died and you are holding a document that says you are in charge of their trust. Almost nobody is ready for this. The order of operations matters more than the speed, and doing the fourth thing first is what turns an ordinary administration into an expensive one.

First, secure the property

Locks, mail, insurance, and any vehicle sitting in a driveway. Insurers treat a vacant house differently from an occupied one and want to be told; a policy that lapses because nobody notified the carrier is a loss the trustee wears personally.

Second, find the assets before you move any of them

Statements, deeds, policies, and anything held at a firm nobody in the family remembers opening. You need a date-of-death value for each one, and for real property and closely held interests that means an appraisal rather than an estimate. Values matter twice: for the beneficiaries, and for the basis step-up that decides what tax they pay if they later sell.

Third, send the notice

California requires a formal notification to beneficiaries and to heirs after a trust becomes irrevocable, and it carries a deadline measured in days rather than months. Trustees skip it constantly, usually out of delicacy toward a grieving family. The effect of skipping it is the opposite of kind: the period in which someone can contest the trust does not begin until the notice goes out, so it stays open indefinitely.

Fourth, keep records from day one

Every disbursement, every fee, every reimbursement to yourself. Beneficiaries are entitled to an accounting, and reconstructing one a year later from bank statements and memory is the single most expensive thing in most administrations. Built as you go it is a morning's work a month.

And do not distribute yet