Imagine for a moment how you use your desk at home, and at work. At home, you can leave things on your desk, and no-one will disturb it (in this analogy!)
But at work there is say 10 people using 3 desks (you are not all there at the same time). You may not even use the same desk every time. Which means you have to get all your stuff from your shelf, and put it on the desk, and put it back when you are done.
Now, imagine for a moment, the server is the shelves you keep all your work stuff on, and when you log on to any workstation, it is the same as getting all your information files etc, and bringing (loading) it into the PC you are sat at.
Logging off, is the same as putting all your stuff back on the shelves.
If you log onto a different PC, you will still get all your information loaded to that machine.
Different PC's in the office may have different resources (printer, scanner, better video screen etc) or programs loaded (graphic package on the machine with the scanner for example) which means those things might appear slightly different from PC to the next.
In brief, all you're personal files etc, move to whenever you log in.
However, your PC desktop may look slightly different. | 
