I'm guessing you are from Quebec... so I think you're being genuine. I'll give you some quick responses as a fellow fan, not from an umpire
- I'm assuming you are talking about MLB
1) If the catcher has the ball, any contact at the plate is legal. The catcher is allowed to use his body to block the plate if a play is about to occur. If no play, then he needs to just let the runner score.
2) If there is a "force" all a fielder needs to do is touch the base with his foot. If there is not a force, the runner must be tagged. A force happens when a runner must try to advance because the batter has hit the ball, and the runner has to run because his place on the base is needed by a runner behind him.
3) This isn't really a rule, but players who hit for contact are just trying to get the ball in play, while power hitters typically try to hit the ball far. Depends on who the batter is. Bigger hitters try to hit it farther, typically, while faster hitters try to get it in play and make it to first.
4) A fastball is a pitch that is thrown as hard as possible. A change up is a pitch that goes slower and tries to fool the batter (its a change from normal speed). A curveball is a pitch that the pitcher puts spin on so the ball curves as it comes to the plate. A slider is thrown a bit differently then a curveball - basically a harder curveball that moves left and right more than up and down.
5) Any time the ball is in play, a runner may try to advance. The ball is out of play on foul balls and any time the umpire decides to stop play for whatever reason (perhaps to change the ball).
6) Only the batter is out. All runners must return to where they were before the hit before trying to run.
7) Bunting is a technique used by fast players to try to reach 1st base rather than swinging at the ball. Its also used when teams decide to advance a runner to another base and allow the defense to get the batter out. This is called a "sacrifice". Particularly good when you are down by just one run, and want to get a runner closer to home plate rather than try to get another hit and risk an out.
Keep watching the game with another fan, as others said. You'll learn more and more as you watch more and more games. Lastly, since this an umpire forum, you'll find that people here generally talk about very specific rules or how umpires run the game. Another site's message boards like espn.com or any other sports site for fans may prove to be useful for yourself to learn more about how fans view baseball
Enjoy the game, nothing else like it.