join organic group

Hi, im building a social network and i did add OG but i can't put a join link to allow users to join groups
what can i do?

I'm building a website that consist of a main website and three office locations/branches websites. The main website pulls content from all three locations.

Location websites must have a 'home page' with a unique url, as well as the main website ofcourse. Each location must have an allocated admin role that can manage that location content only.

As the title suggests, I am trying to use the rules module to add a Role on joining a specific organic group.

There doesnt seem to be any module for drupal 6.xx (unlike drupal 5.xx). Rules seems like it should be a good fit for this.

This is my first time using this module. I ran through some examples, etc. to get familiar with it.

I Choose >> Triggered Rules

-Add new rule.
Event = User Joins Group

-Add Action
Add Role (then choose the role I want added).

No problem.