Here is the link for the Social Security Administrations booklet for Widows on Survivors Benefits.
The United States Social Security Administration
Look up at the menu for Information for...
Then on the next page click on information for .... Women
It will take you to a page where, at the bottom, is a link to download their booklet on Survivors Benefits in PDF form.
If you cannot find the answer to your question, it might be best to call them at the 800 number or even make an appointment to get your questions asked in person.
I found them to be very helpful when I applied. They anticipated my questions and were very professional and helpful.
Also, just because you make an appointment to go in, you are NOT obligated to apply that day. You can take the information they print out and go home to consider it. When you are ready you can go back on another appointment.