If you mean join a sig campaign, first go here,
https://bitcointalk.org/index.php?topic=615953.0, pic a campaign that accepts newbies, I will be using the 777coin campaign for this tutorial,
https://bitcointalk.org/index.php?topic=840124.0First, read the campaign thread and see if they have spots available and also look for what you should put in your signature.
The thing you would put in your sig space would be
★☆★ 777Coin - The Exciting Bitcoin Casino! ★☆★
First copy that, Head to profile, then click the
forum profile information link and scroll down to where you see signature and a large empty box, paste the code in there and click
change profile at the bottom of the page.
Now go the thread and reply with your rank, activity, posts and address and wait for confirmation