You should have the option in the comment box, if you don't you will need a slope head mod to help you and that is like asking for Allah to appear and give you some dope. Considering that you are new...some new users may not be allowed those privileges yet before you reach 20.00 in points. The old LL..new users were not allowed to fap and thumb anyone up or down until reaching 20.00.
In any case, if it's there..simply click the </> in the comment box. Post your link, etc etc. Good luck.