Karma is only given by the staff (TamaGuides and Admin Staff) and the topic link I have given you also explains more about what to expect (and what not to expect) from Karma
You can like posts on the forums by clicking on the little "Like This" box that appears in the bottom right hand corner of each reply posted on the forums.
This is for members to show that they like the post beause it is useful or friendly or funny.
Hope that helps - but please feel free to send a PM to any of the TamaGuides if you have more questions after you have read through the karma guidelines topic.