First of all I’m sorry for your loss.
You need to contact a law firm and an accounting firm that specialized in “Wills and Estates” as soon as practicable. The first mistake is usually not using a professional who does not specialize in this area as there are other requirements that need to be met.
Perhaps friends in California can be of assistance to you in finding qualified professionals. You need to use the services of an attorney in licensed to practice law in the state of California as your friend was a resident there. They will start the procedures of submitting a copy of the will to the Probate Court. The court will issue a Letter of Testamentary. This will permit you to act on the behalf of the estate in all affairs as Executor of the estate. Fees can be paid from the trust to the attorneys and accountants and other professionals. You too as Executor are entitled to reasonable fees incurred by you in connection with the administration of the estate.