The whole point to golf is to get the golf ball into the hole at the end of the fairway in as few turns as possible. Most gold courses have 18 holes but there are a few with 9 holes.  There are two different types of play in golf a match play or stroke play.
In match play the winner is determined by how many holes are lost or won. The winner when playing by stroke play is determined by who has the lower number of strokes over the entire 18 wholes. Most of professional golf uses stroke play. The most important rules to remember when playing golf are that you have to play the course as you find it and the ball is always played where it lies.
What type of play you chose will really depend on whom you are playing with. Tournaments will have their own rules but if you are just out for some golf with friends then it is up to your group. Just remember to have fun and enjoy the day out on the golf course.