1. go to your Bio Thread and copy the link.
2. go to User CP and click edit Signature.
3. Use the insert Link Icon and paste your Bio link, when you do that you'll notice a new highlighted text, type whatever you want in there, that'll show instead of the whole Link address.
5. Use the Center/Bold/Italic to customize how it will look and where you wanna put it.
then paste it into there. And edit the highlighted bit with the name of your bio or whatever you want to write within it. To get to edit your signature go to user Cp (top left) then go to Edit signature.
If you still don't understand post any questions here.