Create many-to-many relationships between posts of any type using Post 2 Post Plugin

I want to create relationships between posts of any type: post, page, custom etc. by using http://wordpress.org/extend/plugins/posts-to-posts/ Plugin but unable use Registering a connection type in the functions.php file of Edublog Theme.

Following are is the basic usage Guider.
https://github.com/scribu/wp-posts-to-posts/wiki/Basic-usage

Is there any one who help me in this.

Thanks in Advance
Jatinder Dhiman