My b2evolution Version: 2.4.2

Hello

I imagine that this is a pretty basic question, so forgive me if its an obvious answer. I can't seem to add a button to the right column of my blog that allows people to register for my blog as a user so that they can create their own posts. Here is my blog:

http://www.theaubribrownclub.org/blog/

I want exactly what is featured on this blog - http://www.tcpaul.com/blogs/index.php where there's a section in the right column titled "User Tools" and a button called "Register" for users to create their own account.

I can't find anything in my blog administration that allows me to add this option. It came standard as part of previous versions of b2evlolution software, but does not appear to be included in the latest 2.4 version.

Can anyone help me please? Thanks.