If someone dies with no spouse, how do his children go about obtaining his property and assets?

If this person died without any life or estate planning, his children will likely have to open a formal probate to distribute his property and assets.  There are several ways to transfer assets upon death that do not require probate, and you should check to see if any of this was done before opening a formal probate.

First, check the deed to any real property.  If another person or persons are listed on the deed, the property may pass automatically to that person(s).  The way the title is written determines whether all of the property passes to the other.  In general, if the deed says that the property is transferred to Person A and Person B "as joint tenants with right of survivorship," then it will pass automatically.  (PLEASE do not use this general answer to prepare a deed. Check with a proper authority to make sure the language meets exactly the requirements of your state.)

Next, check the titles to any other assets to see if another person or persons is listed.  In most states, including Florida, a second "joint owner" owns the asset if the first passes away.

Next, check the bank and investment accounts to see if a second person is listed on the account, or the account was designated as a "pay on death" (POD) or "transfer on death" (TOD) account.  If so, the funds in this account will be paid to the beneficiary listed on the POD or TOD paperwork.

Next, look for insurance policies and call the carrier to find out if the deceased listed a beneficiary.  If so, the carrier will pay the beneficiary directly.

Finally, call the administrator for all retirement accounts to find out who is listed as the beneficiary on those accounts.  IRA's, 401k's, and other retirement accounts usually require a beneficiary, so there should be a beneficiary listed.  The beneficiary may be the deceased person's estate, but usually an individual is listed.

All of these methods "avoid probate" and do not require a formal estate administration ("probate").  If the deceased did none of this, and had no will or trust, the children will have to hire an attorney and open an estate to transfer the assets.  If the assets are few, your state may have a quicker/easier procedure to handle this.  Florida, for example, has a "summary administration" procedure that is quicker and easier than a full administration.

Hope this helps.