Hey man! Whenever you go to reply to a topic, or edit your signature, and the message box with all the smilies and stuff pops up. towards the top of that box, right under the white smiley is a little picture that when you mouse over it it says, "insert link" Click that, a little box will pop up, then just copy and paste whatever link you want into it. Once you've done that, hit "Ok" the URL will then appear in the message box. You will notice that "part" of it is highlighted white, hit the space bar, and that part will dissappear, once you do that, just start typing whatever you want the link to say. The important part is to not hit the "enter" key, just start typing whatever you want to name it. the computer will do the rest. Also, Leave the remaining part of the URL where it is. It will dissappear once you hit sumit.
Once you do that, just hit the post/sumit button and you are good to go! Just holler if you have any other questions. I'll be glad to help!