Guild Wars 2

I’ve read about them but not sure how to use them, I think i accidentally use them, but have never used them on purpose?

Lay down a combo field then do a combo finisher.

combo’s are used when you combine a combo field with a combo finisher.

Combo fields differ by element. For example you have fire, ice, water, lightning, light, dark, smoke, ether and so on combo fields.

Combo finishers differ by method of attack. You have blast, whirl, leap, and projectile.

Each combo field has different effects based on which combo finisher you use.

To use a combo, simply lay down a combo field, then use a combo finisher inside it (Note: some combo fields are specific in their area. For example the elementalist burning speed, unless your skill passes through, or is used on the actual fire animation it wont proc the combo effect)

You can also use finishers into other players fields, or vice versa.

Combo fields can range from incredibly handy (some elementalist attack rotations give their team 12+ stacks of might in a few seconds)
to essentially useless (some combo fields have minimal utility, or add effects that can be commonly found elsewhere)

First step: go to the wiki and search ‘combo’.
You’ll find a list of all the possibilities there.
So what field (light, fire, water,poison, etc) give what result, depending on the finisher you use (blast, projectile, leap, …)

This link:

http://wiki.guildwars2.com/wiki/Combos

Than see what your profession has in terms of fields and finishers.
In the Wiki page you can click on each field or finisher to see details on who can do them, and how.

Remember you can combine with other players, so if you just have a good finisher, see who can provide the field.

Than go test your own combinations in the Mists, some you have time (a field of 10 seconds), some you need to be really fast (a field of 2 seonds and only a timed blast finisher…)

Last step: in fights with other players, learn to recognise what fields they are putting down, and react to those.
Also: put your own fields down, so others can benefit from it.

Depends on the skills you use.
Wiki on Combo Fields

If you have a Combo Field, you place it down on an ally or in the path of their projectiles, and hope they use their Combo Finishers. In really good groups with Voice, you can call it out what field you are putting down and get everyone ready to combo with it.

If you have a Combo Finisher, you simply need to use the skill in question inside the field/effect or have the projectile go through the field/effect.
Combo Finisher: Whirl – Inside of Combo Field.
Combo Finisher: Blast – Inside of Combo Field.
Combo Finisher: Leap – Inside or through Combo Field
Combo Finisher: Projectile Inside or through Combo Field.
If you only have Finishers, simply look for an allies’ effect on the ground and see if one of your finishers gives you something extra.

If you have both, you can pull off combos by yourself.

As a Mesmer, its very common to do a self-combo with Chaos Storm(Combo Field: Ethereal) and Phase Retreat(Combo Finisher: Leap) for a few seconds of Chaos Armor buff. While a Mesmer only has access to Combo Field: Ethereal and one Combo Field: Light, we can sneak in any type of Combo Finisher depending on our weapon selection.

thank you for helping