To play golf, you need a golf course. A golf course generally comprises 18 holes. Though there are plenty of nine-hole courses as well. A round of golf is complete when you play the entire 18 holes.
A hole starts from the tee area, from where you hit your first shot, and ends at a green, where the actual hole is located into which you have to put your ball. Each hole on a course is of fixed length. It can be 167 yards from tee to green, or 356 yards or even 575 yards.

Depending on the length of the hole, you are designated certain number of strokes to complete it. That's call 'par' of the hole. A short hole can be par-3, a medium length hole can be par-4, while longer holes are par-5. A good player is expected to complete the hole in that many strokes, or even lesser.
If the pars of all the holes are counted, it generally adds up to 72. That's called the par of the course. You can even have a par-70 or a par-73 course. A typical 18-hole course has four par-3s, four par-5s and 10 par-4s, though this may differ from course to course.

The area between the tee and green is called the fairway. It is expected that you hit your shots into the fairway. If you are not accurate, you might end in the rough (area around the fairway where the grass is kept longer thus making your shot difficult), or bushes and trees which can hinder you shot towards the green.

To make the hole even more difficult, you have man-made or natural 'hazards'. The most common are the 'sand traps' or 'bunkers' (an area dug up and filled with sand) and water hazards (natural or man-made ponds, lakes, ditches or canals). Playing a shot from the bunker is lot more difficult than playing it from the fairway. But if you enter a pond, you either play from inside the water, or take penalty drop, thus losing strokes.

On the green area, the grass is cut extremely short and even, giving it a carpet-like feel. Once you reach the green, you have to 'putt' the ball, i.e., roll it into the hole with the help of your putter.