سہارا are just props. آپ give them to someone when آپ feel they've done یا accomplished something. They serve no real purpose otherwise. Personally I find them useless, which is why I don't have any.
Just go to a person's پروفائل and click on their wall. After doing so, آپ should see a سہارا button near the emoticon button and the bottom left of the wall. Click on that and then you'll have an option of giving people all sorts of props. You're welcome.
