Some basic questions about Football?

Hi everyone! I'm 17 and I'm new for football, I came from a country that doesn't have football, but now I start to like this sport and want to learn more about it.

These are some questions:

1. There was a game I watch yesterday and this one team play in a weird way that I never seen before, they runned and passed the ball for like many times around the team, I don't understand why they do it, for what and what does it calls?

2. I read some books about high school football players and learned that many of the players using drugs such as steroid or Vicodins to be bigger and stronger, isn't illegal? and how come no one check their blood stream? is that true that u must use those to be better?

3. what's kind of gear do I need to play football? shoes? protection gears?

4. I'm 5ft 7' and 145lbs, am I too small? what position should I play?

5. is there any good websites that I can find all information about playing football in Daly City, CA?

6. What make a NFL team qualified to the Super Bowl championship game?

7. What is the most important BOWL for the NFL teams?

Thank you for your help and happy holidays!