I need to know how to change Spark Plugs on my VW Passat 1.8 20v

You will need to remove the top engine cover, this is just pushed on, with a little effort it can be lifted off, You will then see 4 caps with wires connected, Press in the locking lugs and disconnect the wires of all 4, you will then need to pull the coils out one at a time, ( may need help of a small lever, but be careful not to damage casings ) plugs can then be seen inside of the head, You will need a long plug spanner ( normally in tool kit of car ) undo them in anti clockwise motion and remove plugs, refit in reverse of above