Vaal Pact???

how can i use vaal pact?, a already allocated a skill on. is it like a support gem?, if so how can i link it to my skill gem?, i'm just new so sorry i really don't know what to do thanks!!!!

and more power to Grinding Gear Games :-)

ok for Vaal Pact to work you need either a Life Leech Node in the Tree. Or Life Leech on an item, or a skill linked to a life leech gem.
However Vaal Pact is a skill that is not for the faint of heart! You do not regain any health outside of the city except from life leech and life on hit.
Those are gems as well as affixes for items (weapons for example)
my advise would be, you do not spec vaal pact until you have firm grasp of the concepts of life leech and skill links and the likes.

So life gain on hit DOES work with Vaal's Pact? That's good news. Now I just have to figure out what percent life leech is better than 40 LGOH.

at 4% life leach you would need about 1600-1700 dps to make up for 40 lgoh. Well, for me anyways playing a dual wield elemental cleave templar. You also have to take in to account rather or not it's physical only lifeleech from a piece of gear or all damage done like from the gem. Also how fast you attack. IF you do good dps, but also attack very fast, then lgoh might be better. There is a calculator somewhere but I'm not sure where. If I'm fighting a elemental resist pack then lgoh might be better because I'm doing less damage over all. I wouldn't recommend playing Vaal pact at all, if you find yourself in a shitty situation where you have to bounce out, you have no way to recover life on the run, I'm not sure if instant heal flasks work or not. If they do then I'm probably wrong. Lgoh + Vaal Pact and instant flasks sounds pretty tanky.

vaal pact i believe is 0 regeneration and lifesteal and lifegain on hit effects are instant over the regenerative effect without vaal pact, so pots become useless i guess.