Death without a Named Beneficiary

HELP!( In Georgia)
I have been reading on your site about Death without a Named Beneficiary and I am very confused (just not smart enough to understand),
What I would like to know is this.
(1)Do you have to put down a beneficiary on a life policy when you buy it?
(2)If beneficiary is spouse and they are deceased then does it go to children or to the Estate?
(3) If there is no beneficiary listed, spouse is deceased and there are children and there is an Estate where does it go?
(4)If life Insurance are paid to an Estate can this be done before probating a will and can life Insurance Checks be paid directly to a Funeral Home


Thank You!!!
Bee