Field Goals and Overtime

[Gemini]

Questions came up last night at our high school game in Georgia. With 10 seconds left, we went for a field goal. It was good and we went ahead by 3. If we had missed the field goal on 2nd down, would we have had two more tries on third and fourth down?" If so where would they have spotted the ball? Another question about overtime? What is National Federation's overtime rule?

Thank you in advance for your replies. I am a baseball and softball official, and I do not know many of the football rules.