How Do You Add Comment Signatures?

This is honestly a pretty silly question, but how does one add those little comment signatures (the ones underneath the line)? Is there an html code, or...?

Click Profile, then Edit.

I'm a bit confused, I clicked profile, but I can only seem to find things editing names and contact info...

Right now, you should see a black box in the top right corner, and the word profile above it. Clicking on profile gives you a new screen, that black box has changed to display your profile. Beneath it, you can find the edit button.

Click that to bring up a new screen. In the main screen you'll see things like name, etc. At the very bottom it says Signature and there is a bit to put your signature in.

Ohhhh, I see now.

I was clicking the profile button on the main page, not the forum. I probably shouldn't checked that too.