How do you trap Souls on skyrim i have gems but when i try to click on people it does'nt work.

find a soul trap spell or a weapon enchanted with soul trap

First off, you need a way to cast soul trap, be it by casting through a spell, or as a weapon enchantment. When you've got those, cast the soul trap spell/hit an enemy with a soul trap enchanted weapon, and kill them before the effect wears off (I find it the easiest to just have a soul trap enchanted weapon, as the effect will constantly be applied when you hit them). Then, you need to have empty soul gems. Petty, common, lesser, greater and grand soul gems will only trap creatures, whilst black soul gems can only trap NPCs (i.e people). The different types of soul gems correspond with how strong of a soul they can trap. http://uesp.net/wiki/Skyrim:Souls

When you've successfully captured a soul, it will be stored in the most compatible soul gem in your inventory. For example, if you have an empty petty and lesser soul gem, and you successfully capture a skeever's soul (petty) it will be stored in the petty soul gem. However, if you were to capture another skeever soul after that, it will fill up the lesser soul gem, so be careful when you have multiple empty soul gems in your inventory.

Thx i dont have any soul trap enchanted weapon tho. i just wanna Enchante my weapons.. but i cant.. im not a mage. thanks anyways ill figure it out i hope.