Once you've completed the preceding Timeline tasks, you can wrap up the estate settlement process:
Distribute the net estate assets to the heirs in accordance with the asset disposition plan you developed. See Making Distributions.
If you planned to compensate the executor, make that payment now. See Executor Compensation.
If the estate went through an official probate process, you must submit (and get approved) a "Final Accounting", which shows how you handled the estate assets: what income the estate generated, what losses, how much you paid the individual creditors, and how much you distributed to heirs. You must also submit (and get approved) a "Closing Statement", stating that you have resolved all debts, paid all taxes dues, and distributed the estate net proceeds appropriately.
By this time, there shouldn't be anything left in the estate, other than perhaps the estate bank account you opened. You probably closed this account when you distributed the proceeds, but if not, now's the time.
If you filed a Form 56 with the IRS when you became an executor (or at any time), you should now file a corresponding Form 56, notifying the IRS of the termination of your responsibilities.
Congratulations: You're done! See also Wrapping It Up.