I guess moneymoney has already explained you everything ...
To just make it simple .... You can sell your signature space ... And comlete offers to earn from the forum.
In order to sell your signature space go to the link moneymoney gave you and then copy paste any of the signature code into your signature space ..
After that you need to open a thread in Information Board thread title being "Username(Your username in cashtalk forum) Bonuses"
Inside you should place your profile link of the forum in which you have placed your referral link, along with that you need to mention how many posts you have at the moment of posting the code.

Thats all and every month you will be paid for the number of posts you make during that month.