Trapping hints, please?

I'm new to the game, only have Prophecies, and want to learn how to use traps.

How exactly do they get activated? When the enemy gets close to them? Do I still have to be there?

What traps are best and why?

If I was in the middle of a battle and set a trap, would it activate immediately? Provided I'm not interrupted, of course.

Thanks in advance.

Chris

Traps are set at a certain area and activated when an enemy passes over that area that the trap was laid. A good spot to learn about traps would be from the following links:

http://gw.gamewikis.org/wiki/Trap

http://gw.gamewikis.org/wiki/General_trapping_guide

If you only have prophecies, then you can make a good trapping build with the following skills:

[skill]Whirling Defense[/skill] and [skill]Oath Shot[/skill]

Trappers used to use [skill]Mantra of Resolve[/skill], but the skill was changed and now causes a large energy loss when it prevents interuption and therefore is not a good choice anymore.