It's pretty easy and intuitive compared to the original release of the game years ago. When you have a quest being tracked, open up the map and mouse over it on the Quest Legend (it's dragable) and the area you need to head to blinks in the color indicated to the right of the quest in the legend. If you're turning the quest in rather than doing its requirements, it will be in the shape of a ring and it will blink too.
M is the hotkey to open the map.
nice, thanks for the tip!