Using WPMU affiliates plugin and want to know how affiliate gets credit on new user registeration

I need some help to set up WPMU affiliates plugin. One user has this URL( And when other users signup through this url 'Sign ups' count increases for this affiliate, as in screenshot you can see 'Signups count' for 'testbreezy' is 2. But I dont know how an affiliate will get 'Rewards' or 'Credit' when a new user register for an affiliate.